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	2022-12-08: How Are Quasiparticles Different From Particles? 05:43: But this seems a bit more like a sound wave than a particle. 05:47: In fact sound waves in solids do propagate exactly like this. 06:25: ... via these vibrations - so this makes the phonon a quantum of a sound wave, similar to how a photon is a quantum of light - of an electromagnetic ... 13:28: ... appear in lattices of quantum spin, like are magnons - quanta of waves in that lattice, or skyrmions, which are localized, stable topological ... 05:47: In fact sound waves in solids do propagate exactly like this. 13:28: ... appear in lattices of quantum spin, like are magnons - quanta of waves in that lattice, or skyrmions, which are localized, stable topological ... 06:44: They travel at the speed of their wave-type - sound in this case.
	2022-11-23: How To See Black Holes By Catching Neutrinos 00:30: There’s the James Webb Space Telescope and its infrared supervision and of course LIGO with its ability to see gravitational waves. 04:32: ... expanding EM waves created by the charged particle expand slower than the particle itself, ... 12:01: ... can also look for neutrino Cherenkov radiation at radio wavelengths, which allows us to scan vast tracks of the Antarctic glacier with ... 00:30: There’s the James Webb Space Telescope and its infrared supervision and of course LIGO with its ability to see gravitational waves. 04:32: ... expanding EM waves created by the charged particle expand slower than the particle itself, ...
	2022-11-09: What If Humanity Is Among The First Spacefaring Civilizations? 18:34: They imagined waves traveling from both cause to effect and from effect to cause. 18:50: ... with the time-reversed signals corresponding to negative frequency waves. ... 17:08: ... Tch and zomgthisisawesomelol point out that Einstein was referring to wavefunction collapse when he said "spooky action at a distance" not quantum ... 17:23: ... was referring to general wavefunction collapse, in which the wavefunction appears to change everywhere at the ... 17:37: ... and basically discovered quantum entanglement in an effort to disprove wavefunction collapse through a reductio ad ... 17:49: He showed that instant collapse of entangle wavefunctions led to crazy FTL-like effects, and so thought it couldn’t be real. 18:04: So, “spooky action at a distance” does refer to wavefunction collapse, including to the wavefunction collapse of entangled particles. 20:25: This branch of my wavefunction only remembers not going to any of them, but I assume the other guy had a really great time. 17:08: ... Tch and zomgthisisawesomelol point out that Einstein was referring to wavefunction collapse when he said "spooky action at a distance" not quantum ... 17:23: ... was referring to general wavefunction collapse, in which the wavefunction appears to change everywhere at the ... 17:37: ... and basically discovered quantum entanglement in an effort to disprove wavefunction collapse through a reductio ad ... 18:04: So, “spooky action at a distance” does refer to wavefunction collapse, including to the wavefunction collapse of entangled particles. 20:25: This branch of my wavefunction only remembers not going to any of them, but I assume the other guy had a really great time. 17:23: ... was referring to general wavefunction collapse, in which the wavefunction appears to change everywhere at the instant a measurement is made, in apparent ... 17:08: ... Tch and zomgthisisawesomelol point out that Einstein was referring to wavefunction collapse when he said "spooky action at a distance" not quantum entanglement as ... 17:23: ... was referring to general wavefunction collapse, in which the wavefunction appears to change everywhere at the instant a ... 17:37: ... and basically discovered quantum entanglement in an effort to disprove wavefunction collapse through a reductio ad ... 18:04: So, “spooky action at a distance” does refer to wavefunction collapse, including to the wavefunction collapse of entangled particles. 17:49: He showed that instant collapse of entangle wavefunctions led to crazy FTL-like effects, and so thought it couldn’t be real. 18:34: They imagined waves traveling from both cause to effect and from effect to cause. 18:50: ... with the time-reversed signals corresponding to negative frequency waves. ... 18:34: They imagined waves traveling from both cause to effect and from effect to cause.
	2022-10-26: Why Did Quantum Entanglement Win the Nobel Prize in Physics? 04:21: David Bohm got the worst of that with his pilot wave theory, which we talk about in another video. 03:07: Quantum systems are described by a mathematical object called the wavefunction, which evolves according to the Schrodinger equation. 03:13: ... joint wavefunction of two entangled objects only contains information about the ... 03:22: They only gain specific values when  observed and the wavefunction “collapses”. 03:28: For our quantum balls to know their own color the whole time, there would need to be extra information not contained in their wavefunction. 03:46: ... exist, while others like Neils Bohr insisted that the wavefunction was the complete  description of a quantum ... 12:04: But there could still be hidden variables that exist in the global wavefunction of the entangled particles. 03:07: Quantum systems are described by a mathematical object called the wavefunction, which evolves according to the Schrodinger equation. 03:13: ... joint wavefunction of two entangled objects only contains information about the ... 03:22: They only gain specific values when  observed and the wavefunction “collapses”. 03:28: For our quantum balls to know their own color the whole time, there would need to be extra information not contained in their wavefunction. 03:46: ... exist, while others like Neils Bohr insisted that the wavefunction was the complete  description of a quantum ... 12:04: But there could still be hidden variables that exist in the global wavefunction of the entangled particles. 03:22: They only gain specific values when  observed and the wavefunction “collapses”.
	2022-10-19: The Equation That Explains (Nearly) Everything! 01:33: ... example, if we insist that the phase of the quantum wavefunction is fundamentally unmeasurable, then we need to add a term to the ... 02:21: ... symmetries also come from the fact that the wavefunction can be distorted in different ways that have no effect on the laws of ... 04:36: ... it seems like it might be a good idea to figure out the Lagrangian for a wavefunction that has our symmetries of interest. And that is exactly what the ... 09:24: ... That’s what the second term in the Lagrangian represents. The psi is the wavefunction of the fermion fields. Strictly speaking there are 12 fields for the 12 ... 13:49: ... it works. Putting in your particle wavefunction and setting your indices right and including the correct masses, you can ... 01:33: ... example, if we insist that the phase of the quantum wavefunction is fundamentally unmeasurable, then we need to add a term to the ... 02:21: ... symmetries also come from the fact that the wavefunction can be distorted in different ways that have no effect on the laws of ... 04:36: ... it seems like it might be a good idea to figure out the Lagrangian for a wavefunction that has our symmetries of interest. And that is exactly what the ... 09:24: ... That’s what the second term in the Lagrangian represents. The psi is the wavefunction of the fermion fields. Strictly speaking there are 12 fields for the 12 ... 13:49: ... it works. Putting in your particle wavefunction and setting your indices right and including the correct masses, you can ...
	2022-10-12: The REAL Possibility of Mapping Alien Planets! 01:25: ... of the electromagnetic wave  - which gets harder the shorter the wavelength. But there is one way to take a direct image of an exoplanet in ... 15:45: ... no - Hubble was most sensitive at visible  and ultraviolet wavelengths, while JWST is   an infrared scope. These are very ... 01:25: ... of the   arrival time and phase of the electromagnetic wave  - which gets harder the shorter the wavelength. But there is one way to ... 10:07: ... first cluster of   craft was the first pearl. Even if that wave  doesn’t get it quite right, its data will help   the next ... 01:25: ... of the   arrival time and phase of the electromagnetic wave  - which gets harder the shorter the wavelength. But there is one way to ... 10:07: ... first cluster of   craft was the first pearl. Even if that wave  doesn’t get it quite right, its data will help   the next pearl learn, ... 01:25: ... is always better.   When light passes into a telescope, its wave nature interacts with the edges of the aperture,   causing ...
	2022-09-28: Why Is 1/137 One of the Greatest Unsolved Problems In Physics? 01:43: ... in the light observed when we break it up into a spectrum of different wavelengths. ... 04:05: ... repulsive energy between two electrons is 137 smaller than a photon with wavelength equal to the  distance between the ... 01:43: ... in the light observed when we break it up into a spectrum of different wavelengths. ...
	2022-09-21: Science of the James Webb Telescope Explained! 03:54: The choice of long wavelength light specializes JWST for a number of particular science goals. 04:40: ... stars, as well as peer through that dust which normally blocks shorter wavelength ... 05:16: ... with sensitivities from visible red light through the slightly longer wavelengths of near-infrared all the way to the much longer wavelength ... 03:54: The choice of long wavelength light specializes JWST for a number of particular science goals. 04:40: ... stars, as well as peer through that dust which normally blocks shorter wavelength light. ... 03:54: The choice of long wavelength light specializes JWST for a number of particular science goals. 05:16: ... longer wavelengths of near-infrared all the way to the much longer wavelength mid-infrared. ...
	2022-08-03: What Happens Inside a Proton? 00:45: ... are particles in the universe to store all the information in the wavefunction of a single large   molecule. We also talked about the hack ...
	2022-07-27: How Many States Of Matter Are There? 10:24: The frequent interactions between people cause liquid-like phenomena like currents and waves as individuals lose their autonomy of motion.
	2022-07-20: What If We Live in a Superdeterministic Universe? 01:12: Pilot wave theory, objective collapse models, and even the Many Worlds interpretation all seek to describe a reality that exists sans observers. 07:59: Things like pilot wave theory and objective collapse models try to do that. 01:12: Pilot wave theory, objective collapse models, and even the Many Worlds interpretation all seek to describe a reality that exists sans observers. 07:59: Things like pilot wave theory and objective collapse models try to do that. 01:12: Pilot wave theory, objective collapse models, and even the Many Worlds interpretation all seek to describe a reality that exists sans observers. 02:20: ... quantum mechanics, the fundamental building block of reality is the wavefunction, which describes the evolving probability distribution of all possible ... 02:33: The results of your measurements are plucked from the wavefunction of whatever you’re observing. 02:39: We say that measurement “collapses” the wavefunction, obliterating all potential results in favor of one actual result. 02:45: A wavefunction can span multiple distinct, even contradictory states. 02:56: And a wavefunction can also span multiple particles, holding information about the relationships between those particles. 05:34: ... about its own physical state, in a way that was somehow hidden from the wavefunction of standard quantum ... 02:20: ... quantum mechanics, the fundamental building block of reality is the wavefunction, which describes the evolving probability distribution of all possible ... 02:33: The results of your measurements are plucked from the wavefunction of whatever you’re observing. 02:39: We say that measurement “collapses” the wavefunction, obliterating all potential results in favor of one actual result. 02:45: A wavefunction can span multiple distinct, even contradictory states. 02:56: And a wavefunction can also span multiple particles, holding information about the relationships between those particles. 05:34: ... about its own physical state, in a way that was somehow hidden from the wavefunction of standard quantum ... 02:39: We say that measurement “collapses” the wavefunction, obliterating all potential results in favor of one actual result.
	2022-06-22: Is Interstellar Travel Impossible? 16:16: Yash Chaurasia asks whether asking an electron "are you a particle?" automatically answers "are you a wave?”. 16:34: But if there are only two possible answers - particle or wave - then asking one answers the other. 17:09: ... can either ask about the wave-like properties (for example the phase), or about the particle-like ... 16:24: ... refresh your memory, the wave-particle duality was explained in the context of informational quantum mechanics ... 16:41: ... are the most elementary, and so we don’t know if a quantum system’s wave-particle nature has a binary ... 16:24: ... refresh your memory, the wave-particle duality was explained in the context of informational quantum mechanics ... 16:41: ... are the most elementary, and so we don’t know if a quantum system’s wave-particle nature has a binary ... 16:24: ... refresh your memory, the wave-particle duality was explained in the context of informational quantum mechanics in that ... 16:41: ... are the most elementary, and so we don’t know if a quantum system’s wave-particle nature has a binary ...
	2022-06-15: Can Wormholes Solve The Black Hole Information Paradox? 07:24: ... tidal wave of math in these papers  pulls ideas from string theory, ...
	2022-06-01: What If Physics IS NOT Describing Reality? 10:02: ... it passes through the experimental apparatus.   If it’s a wave it travels both paths of the  device, if a particle it must only ... 10:33: ... questions:   “Are you a particle?” And “are  you a wave?” at the same ... 08:49: ... the limited knowledge that   we can extract from a quantum wavefunction. For  example, that the product of the measurement error   ... 10:33: ... uncertainty to the situation,   the team said that the wavefunction contained  only one answer to two complementary ... 11:24: ... In  quantum mechanics, we tend to think of the quantum   wavefunction as pretty fundamental. It describes  the evolving distribution of ... 12:09: ... if the wavefunction is about  the information content of a system,   again, ... 08:49: ... the limited knowledge that   we can extract from a quantum wavefunction. For  example, that the product of the measurement error   ... 10:33: ... uncertainty to the situation,   the team said that the wavefunction contained  only one answer to two complementary ... 11:24: ... In  quantum mechanics, we tend to think of the quantum   wavefunction as pretty fundamental. It describes  the evolving distribution of ... 12:09: ... if the wavefunction is about  the information content of a system,   again, ... 10:33: ... uncertainty to the situation,   the team said that the wavefunction contained  only one answer to two complementary questions:   just as our ... 08:49: ... the limited knowledge that   we can extract from a quantum wavefunction. For  example, that the product of the measurement error   in a ... 10:02: ... experiment. This   experiment causes a photon to behave like a wave  or a particle depending on the question asked   of it. And ... 09:26: ... original and most mysterious features of  quantum mechanics - wave-particle ... 10:33: ... answers   to both questions. So, they found that the  wave-particle duality of quantum mechanics   arises from the limited ... 09:26: ... original and most mysterious features of  quantum mechanics - wave-particle ... 10:33: ... answers   to both questions. So, they found that the  wave-particle duality of quantum mechanics   arises from the limited ... 09:26: ... original and most mysterious features of  quantum mechanics - wave-particle duality. ... 10:33: ... answers   to both questions. So, they found that the  wave-particle duality of quantum mechanics   arises from the limited information, ...
	2022-05-25: The Evolution of the Modern Milky Way Galaxy 03:22: ... disks, and their violent convulsions settled into  the density waves that we see as spiral arms. The   new spiral galaxies ... 05:11: ... from specific elements sucking up  or producing light at specific wavelengths.   Stars with similar metallicities could have come from the same merger ... 03:22: ... disks, and their violent convulsions settled into  the density waves that we see as spiral arms. The   new spiral galaxies ... 12:11: ... formation in about  2 billion years. The accompanying supernova waves   may not be the best thing for life on Earth, but  we do have 2 ...
	2022-05-18: What If the Galactic Habitable Zone LIMITS Intelligent Life? 08:01: ... bulge. As the galactic bulge grew,   it was wracked by further waves of supernovae. As  Moiya mentioned, having excessive exploding ...
	2022-05-04: Space DOES NOT Expand Everywhere 16:38: ... “creates itself” by constructive interference - only electrons whose wavefunction peaks and valleys line up on each orbit can exist. Maybe the universal ... 14:34: ... or “conscious awareness” as the causal event that  collapses the wavefunction,  or in this case manifests the universe. Rather than for example saying ... 16:38: ... is the just that wavefunction in the space of  infinite possible wavefunctions  that constructively interferes to reinforce its own ...
	2022-04-27: How the Higgs Mechanism Give Things Mass 02:31: ... an   example of this. The exact phase of the quantum  wavefunction from one point in space to the   next - local phase - doesn’t ...
	2022-04-20: Does the Universe Create Itself? 01:59: ... in the behavior of the wavefunction, such as de Broglie-Bohm pilot wave theory or objective collapse interpretations. Still others sought to ... 06:24: ... the combination of phase shifts in the beamsplitters causes the photons wavefunction to perfectly line up in detector 1 - constructive interference, and to ... 01:59: ... a real, physical universe could be interpreted in the behavior of the wavefunction, such as de Broglie-Bohm pilot wave theory or objective collapse ... 06:24: ... the combination of phase shifts in the beamsplitters causes the photons wavefunction to perfectly line up in detector 1 - constructive interference, and to ... 16:10: ... fields in a way that looks like thermal radiation. That radiation has a wavelength that’s on the scale of the event horizon. So the horizon radiation from ...
	2022-03-08: Is the Proxima System Our Best Hope For Another Earth? 18:33: When those cosmic strings radiate gravitational waves, how is the Higgs field supposed to smooth itself out? 16:39: ... on the last two episodes: the one on objective collapse theories, where wavefunction collapse is explained as a real, physical ... 16:52: ... the objective collapse episode we talked about some field “hitting” the wavefunction to cause it to collapse, and Kadag asks what exactly is doing the ... 17:04: It has to be a field that has a non-linear influence on the wavefunction. 17:13: But in general it means different branches of the wavefunction are able to influence each other, which is not the case in standard quantum mechanics. 17:27: ... one field that might be able to do this is gravity, in which case the wavefunction is being “hit” by the non-linearities across the wavefunction introduce ... 19:27: ... phase angle is fundamentally unmeasurable - just the the phase of the wavefunction - it’s a symmetry of the Higgs field and doesn’t affect the behavior of ... 16:39: ... on the last two episodes: the one on objective collapse theories, where wavefunction collapse is explained as a real, physical ... 16:52: ... the objective collapse episode we talked about some field “hitting” the wavefunction to cause it to collapse, and Kadag asks what exactly is doing the ... 17:04: It has to be a field that has a non-linear influence on the wavefunction. 17:13: But in general it means different branches of the wavefunction are able to influence each other, which is not the case in standard quantum mechanics. 17:27: ... one field that might be able to do this is gravity, in which case the wavefunction is being “hit” by the non-linearities across the wavefunction introduce ... 19:27: ... phase angle is fundamentally unmeasurable - just the the phase of the wavefunction - it’s a symmetry of the Higgs field and doesn’t affect the behavior of ... 16:39: ... on the last two episodes: the one on objective collapse theories, where wavefunction collapse is explained as a real, physical ... 17:27: ... case the wavefunction is being “hit” by the non-linearities across the wavefunction introduce by spacetime ... 03:33: Proxima’s emissions lines seemed to shift back and forth from the wavelengths dictated by the laws of physics. 04:22: ... the wavelengths of all the star’s light are stretched as the star moves away from us and ... 03:33: Proxima’s emissions lines seemed to shift back and forth from the wavelengths dictated by the laws of physics. 04:22: ... the wavelengths of all the star’s light are stretched as the star moves away from us and ... 03:33: Proxima’s emissions lines seemed to shift back and forth from the wavelengths dictated by the laws of physics. 18:33: When those cosmic strings radiate gravitational waves, how is the Higgs field supposed to smooth itself out?
	2022-02-23: Are Cosmic Strings Cracks in the Universe? 10:09: ... in the kinks causes them to radiate   gravitational waves. In this way cosmic strings  shed energy, and so they slowly decay ... 12:19: ... “regular” cosmic strings in many ways -  like the gravitational waves and the lensing.   But there are differences. While cosmic ... 10:09: ... so we might see flashes  as these beams pass over our gravitational wave   observatories. These are likely too weak to be seen at our current ... 12:19: ... “regular” cosmic strings in many ways -  like the gravitational waves and the lensing.   But there are differences. While cosmic ...
	2022-02-16: Is The Wave Function The Building Block of Reality? 00:49: ... definite properties. Rather they are described by something called the wave function. In fact, a particle is its wave function: a fuzzy distribution ... 01:06: ... to be plucked from the wide range of possible values defined by the wave ... 01:16: We say that the wave function collapses - it appears to shrink to a window whose narrow width is defined by the precision of our measurement. 01:24: ... Prior to opening the box, from the scientist’s perspective the atom’s wave function exists in what we call a superposition of states. It is ... 02:24: ... idea of wave function collapse was first proposed by Werner Heisenberg, one of the ... 03:02: ... span all extremes. John von Neumann and Eugene Wigner thought that wave function collapse happens at the instant of subjective awareness - in ... 03:24: ... example in Hugh Everett’s Many Worlds interpretation, the wave function never collapses, rather lasts forever, splitting into parallel ... 03:52: We've discussed all of theses ideas in the past. But today we’re going to look at a different approach to collapsing the wave function. 03:59: ... that accepts the wave function as the fundamental building block of reality, unlike pilot wave ... 04:36: ... objective collapse theories, wave functions are real, physical entities that literally collapse when ... 05:00: The behavior of the wave function is described by the Schrodinger equation, which tracks its evolution through space and over time. 05:09: ... of what makes superpositions possible - it allows different parts of the wave function corresponding to different possible measurement results to ... 05:44: ... wave function collapse happens, different parts of the wave function interact ... 06:04: ... to model the effect of wave function collapse, Ghirardi, Rimini, and Weber added a non-linear term ... 06:22: ... of this non-linear action as a rare and random hit that the wave function takes at a particular location. That hit causes it to collapse ... 06:53: ... of them experiences collapse, and that single single event collapses the wave function of the entire system. Any attempt to measure an isolated ... 07:44: ... this value, a single particle wave function remains uncollapsed for around 100 million years. But if you ... 08:02: ... interaction with this fluctuating field would continuously collapse the wave function, in contrast to the discrete and violent hits of GRW ... 08:32: ... force. They thought nature already gave us a perfectly good source of wave function collapse: ... 09:25: ... introduces a nonlinear term in the Schrödinger equation, causing the wave function to rapidly and randomly choose to make the object appear either ... 11:09: ... signs of collapse models. For example, the models imply that a quantum wave function will be randomly tossed about and jostled by gravity or some ... 12:55: ... And one that we’ll be coming back to. What, in fact, is the quantum wave function? And how does this abstract system of shifting realities give ... 13:19: ... Level. Ben there are many uncertainties in the world of physics. Is the wave function objectively real? Or is it a statistical or subjective fiction? ... 14:52: ... BuzzBen asks what happens when gravitational waves pass through black holes. Is there gravitational lensing? Well that’s ... 00:49: ... definite properties. Rather they are described by something called the wave function. In fact, a particle is its wave function: a fuzzy distribution of ... 01:06: ... to be plucked from the wide range of possible values defined by the wave function. ... 01:16: We say that the wave function collapses - it appears to shrink to a window whose narrow width is defined by the precision of our measurement. 01:24: ... Prior to opening the box, from the scientist’s perspective the atom’s wave function exists in what we call a superposition of states. It is simultaneously ... 02:24: ... idea of wave function collapse was first proposed by Werner Heisenberg, one of the principle ... 03:02: ... span all extremes. John von Neumann and Eugene Wigner thought that wave function collapse happens at the instant of subjective awareness - in other ... 03:24: ... example in Hugh Everett’s Many Worlds interpretation, the wave function never collapses, rather lasts forever, splitting into parallel ... 03:52: We've discussed all of theses ideas in the past. But today we’re going to look at a different approach to collapsing the wave function. 03:59: ... that accepts the wave function as the fundamental building block of reality, unlike pilot wave theory. ... 04:36: ... to do with a conscious observer or any subjective explanation. The wave function and the collapse are completely real, completely objective — hence the ... 05:00: The behavior of the wave function is described by the Schrodinger equation, which tracks its evolution through space and over time. 05:09: ... of what makes superpositions possible - it allows different parts of the wave function corresponding to different possible measurement results to evolve ... 05:44: ... wave function collapse happens, different parts of the wave function interact with ... 06:04: ... to model the effect of wave function collapse, Ghirardi, Rimini, and Weber added a non-linear term to the ... 06:22: ... of this non-linear action as a rare and random hit that the wave function takes at a particular location. That hit causes it to collapse to a ... 06:53: ... of them experiences collapse, and that single single event collapses the wave function of the entire system. Any attempt to measure an isolated quantum system ... 07:44: ... this value, a single particle wave function remains uncollapsed for around 100 million years. But if you have ... 08:02: ... interaction with this fluctuating field would continuously collapse the wave function, in contrast to the discrete and violent hits of GRW ... 08:32: ... force. They thought nature already gave us a perfectly good source of wave function collapse: ... 09:25: ... introduces a nonlinear term in the Schrödinger equation, causing the wave function to rapidly and randomly choose to make the object appear either “here” ... 11:09: ... signs of collapse models. For example, the models imply that a quantum wave function will be randomly tossed about and jostled by gravity or some other ... 12:55: ... And one that we’ll be coming back to. What, in fact, is the quantum wave function? And how does this abstract system of shifting realities give rise to our ... 13:19: ... Level. Ben there are many uncertainties in the world of physics. Is the wave function objectively real? Or is it a statistical or subjective fiction? Did I ... 02:24: ... idea of wave function collapse was first proposed by Werner Heisenberg, one of the principle founders ... 03:02: ... span all extremes. John von Neumann and Eugene Wigner thought that wave function collapse happens at the instant of subjective awareness - in other words, they ... 05:44: ... wave function collapse happens, different parts of the wave function interact with each other ... 06:04: ... to model the effect of wave function collapse, Ghirardi, Rimini, and Weber added a non-linear term to the Schrodinger ... 08:32: ... force. They thought nature already gave us a perfectly good source of wave function collapse: ... 01:16: We say that the wave function collapses - it appears to shrink to a window whose narrow width is defined by the precision of our measurement. 01:24: ... not. At some point between atom and cat the fuzziness of the atom’s wave function collapses into one of the two states. And becomes or. Decayed and not decayed ... 05:44: ... wave function collapse happens, different parts of the wave function interact with each other instantaneously and non-locally and non-reversibly. This ... 13:19: ... Level. Ben there are many uncertainties in the world of physics. Is the wave function objectively real? Or is it a statistical or subjective fiction? Did I measure ... 07:44: ... this value, a single particle wave function remains uncollapsed for around 100 million years. But if you have Avogadro’s ... 03:24: ... we have the idea of quantum decoherence, where different parts of the wave function simply become unable to interact with each other. We’ve discussed all of these ... 06:22: ... of this non-linear action as a rare and random hit that the wave function takes at a particular location. That hit causes it to collapse to a particular ... 04:36: ... objective collapse theories, wave functions are real, physical entities that literally collapse when they’re ... 03:24: ... all of these ideas in the past. We also have de Broglie-Bohm pilot wave theory, where particles already have defined properties that are hidden within ... 03:59: ... wave function as the fundamental building block of reality, unlike pilot wave theory. And one which avoids multiple universes by insisting that collapse does ... 14:52: ... relative size of the black hole and the wave. A gravitational wave whose wavelength is short compared to the black hole’s event horizon can be completely ...
	2022-02-10: The Nature of Space and Time AMA 00:03: ... what we call the doppler shift which is the [Music] stretching of a wave be it light or sound emits by a moving object simply because if you ...
	2022-01-27: How Does Gravity Escape A Black Hole? 02:02: For example we have gravitational waves - ripples in spacetime caused by certain types of motion. 02:08: ... at the speed of light, and that’s been confirmed when gravitational waves from colliding neutron stars reach us at about the same time the ... 02:46: It would take 8 minutes for the Sun’s deep indentation in the fabric of space to smooth itself - in the wake of some pretty crazy gravitational waves. 13:06: ... method for simulating the insane amount of information in the quantum wavefunction with density functional theory, and then went from the tiny to the ... 13:42: ... interesting thought on the matter and I quote: "That a small part of the wavefunction can be used to "reconstruct" the whole wavefunction, or at least the ... 14:03: ... not that the information of the wavefunction can be compressed below it's "true" informational volume, it's that it ... 13:06: ... method for simulating the insane amount of information in the quantum wavefunction with density functional theory, and then went from the tiny to the ... 13:42: ... interesting thought on the matter and I quote: "That a small part of the wavefunction can be used to "reconstruct" the whole wavefunction, or at least the ... 14:03: ... not that the information of the wavefunction can be compressed below it's "true" informational volume, it's that it ... 02:02: For example we have gravitational waves - ripples in spacetime caused by certain types of motion. 02:08: ... at the speed of light, and that’s been confirmed when gravitational waves from colliding neutron stars reach us at about the same time the ... 02:46: It would take 8 minutes for the Sun’s deep indentation in the fabric of space to smooth itself - in the wake of some pretty crazy gravitational waves. 02:02: For example we have gravitational waves - ripples in spacetime caused by certain types of motion.
	2022-01-19: How To Build The Universe in a Computer 00:30: ... spiral structure will be obliterated, gas will be compacted to produce waves of supernovae, and the giant Milkdromeda galaxy will have been ... 10:02: ... watch as galaxies form, with gas and dark matter interacting to produce waves of star formation and supernovae, settling into spiral structures - just ... 00:30: ... spiral structure will be obliterated, gas will be compacted to produce waves of supernovae, and the giant Milkdromeda galaxy will have been ... 10:02: ... watch as galaxies form, with gas and dark matter interacting to produce waves of star formation and supernovae, settling into spiral structures - just ...
	2022-01-12: How To Simulate The Universe With DFT 00:18: That’s how insanely information dense the quantum wavefunction really is. 01:28: In fact you need more particles than exist in the solar system to store the wavefunction of the electrons in a single iron atom. 01:48: ... describes how the wavefunction of a quantum particle - that’s this psi thing - changes over space, ... 02:19: ... can also solve the Schrodinger equation to find the wavefunction, and the square of that wavefunction gives the the probability ... 02:50: That’s nice because then the wavefunction is just a 1-D array of values. 02:55: ... array stores the wavefunction - the distribution of possible locations - it doesn’t store the actual ... 04:52: ... every time we add a particle we increase the dimensionality of the wavefunction. ... 05:25: So it seems like even for a single atom of iron, a fairly run of the mill element, we can’t even store the wavefunction let alone calculate it. 06:48: In quantum mechanics, we’re dealing with the wavefunction, and the wavefunction fills all of configuration space. 08:11: We need to know the wavefunction for every particle everywhere. 10:11: ... density - is just a tiny fragment of the information held in the total wavefunction of all of those ... 10:29: ... without having to go through the impossibly complex many-electron wavefunction. ... 12:22: ... main takeaway is that physicists realised that a tiny sliver of the full wavefunction - the density distribution - could be mapped to all sorts of useful ... 13:15: What does it mean that there exists a map between the low-information slice of the wavefunction and really all the information we want to get from it? 13:35: ... no doubt deeper truths to be found by understanding how the universal wavefunction with its insane hyper dimensionality is connected to the narrow sliver ... 14:25: Peter, the infinite dimensional universal wavefunction barely contains enough information to describe your generosity. 00:18: That’s how insanely information dense the quantum wavefunction really is. 01:28: In fact you need more particles than exist in the solar system to store the wavefunction of the electrons in a single iron atom. 01:48: ... describes how the wavefunction of a quantum particle - that’s this psi thing - changes over space, ... 02:19: ... can also solve the Schrodinger equation to find the wavefunction, and the square of that wavefunction gives the the probability ... 02:50: That’s nice because then the wavefunction is just a 1-D array of values. 02:55: ... array stores the wavefunction - the distribution of possible locations - it doesn’t store the actual ... 04:52: ... every time we add a particle we increase the dimensionality of the wavefunction. ... 05:25: So it seems like even for a single atom of iron, a fairly run of the mill element, we can’t even store the wavefunction let alone calculate it. 06:48: In quantum mechanics, we’re dealing with the wavefunction, and the wavefunction fills all of configuration space. 08:11: We need to know the wavefunction for every particle everywhere. 10:11: ... density - is just a tiny fragment of the information held in the total wavefunction of all of those ... 10:29: ... without having to go through the impossibly complex many-electron wavefunction. ... 12:22: ... main takeaway is that physicists realised that a tiny sliver of the full wavefunction - the density distribution - could be mapped to all sorts of useful ... 13:15: What does it mean that there exists a map between the low-information slice of the wavefunction and really all the information we want to get from it? 13:35: ... no doubt deeper truths to be found by understanding how the universal wavefunction with its insane hyper dimensionality is connected to the narrow sliver ... 14:25: Peter, the infinite dimensional universal wavefunction barely contains enough information to describe your generosity. 02:55: ... array stores the wavefunction - the distribution of possible locations - it doesn’t store the actual ... 12:22: ... main takeaway is that physicists realised that a tiny sliver of the full wavefunction - the density distribution - could be mapped to all sorts of useful ... 14:25: Peter, the infinite dimensional universal wavefunction barely contains enough information to describe your generosity. 06:48: In quantum mechanics, we’re dealing with the wavefunction, and the wavefunction fills all of configuration space.
	2021-12-29: How to Find ALIEN Dyson Spheres 03:05: ... spectrum - light generated by its 6000K surface is distributed at all wavelengths, but it peaks in the visible part of the ... 03:24: ... new thermal spectrum, now at 300 or so Kelvin, with its peak at infrared wavelengths. ... 07:31: Two pure thermal spectra would be stitched into one weird spectrum with too little light at visible wavelengths and too much at infrared wavelengths. 07:41: If we carefully broke up the star’s light with spectrographs spanning a huge wavelength range, we might be able to see two distinct thermal spectra. 08:12: In astronomy, color refers to the ratio of brightnesses at two different wavelengths. 09:20: At visible wavelengths a star’s color might not change much - it’ll just look dimmer. 09:31: But if we measure its colour using an infrared wavelength along with our visible light, we’d find too much of that IR. 07:41: If we carefully broke up the star’s light with spectrographs spanning a huge wavelength range, we might be able to see two distinct thermal spectra. 03:05: ... spectrum - light generated by its 6000K surface is distributed at all wavelengths, but it peaks in the visible part of the ... 03:24: ... new thermal spectrum, now at 300 or so Kelvin, with its peak at infrared wavelengths. ... 07:31: Two pure thermal spectra would be stitched into one weird spectrum with too little light at visible wavelengths and too much at infrared wavelengths. 08:12: In astronomy, color refers to the ratio of brightnesses at two different wavelengths. 09:20: At visible wavelengths a star’s color might not change much - it’ll just look dimmer.
	2021-12-20: What Happens If A Black Hole Hits Earth? 09:03: ... seismic waves would reach all points on the Earth’s surface. Even at the lowest mass ... 17:55: ... string theory. There are simulations that suggest that the gravitational waves created when fuzzball merge should look almost exactly the same as those ... 18:16: ... may be that the so-called ring-down - the waves produced as the merged object settles back into a spheroid - lasts ... 09:03: ... seismic waves would reach all points on the Earth’s surface. Even at the lowest mass ... 17:55: ... string theory. There are simulations that suggest that the gravitational waves created when fuzzball merge should look almost exactly the same as those ... 18:16: ... may be that the so-called ring-down - the waves produced as the merged object settles back into a spheroid - lasts ... 17:55: ... string theory. There are simulations that suggest that the gravitational waves created when fuzzball merge should look almost exactly the same as those ... 18:16: ... may be that the so-called ring-down - the waves produced as the merged object settles back into a spheroid - lasts longer for ...
	2021-12-10: 2021 End of Year AMA! 00:02: ... it plenty but the idea is that every time you know a the evolving wave function in the quantum world sort of makes a decision uh uh in the ...
	2021-11-10: What If Our Understanding of Gravity Is Wrong? 09:15: AQuaL also had the unfortunate prediction of faster-than-light waves in this added scalar field, which broke causality.
	2021-11-02: Is ACTION The Most Fundamental Property in Physics? 11:12: ... of previous versions of quantum mechanics - for example, Schrodinger’s wave mechanics that talks about the evolution of a single wavefunction. This ... 08:39: ... not as a particle with a well-defined trajectory, but as a quantum wavefunction that represents all possible paths it could take. The wavefunction at ... 09:56: ... action existed that was related to the integrated time evolution of the wavefunction. And he realized that this quantity should result in destructive ... 11:12: ... Schrodinger’s wave mechanics that talks about the evolution of a single wavefunction. This is analogous to how Lagrangian mechanics reproduced Newton’s ... 08:39: ... not as a particle with a well-defined trajectory, but as a quantum wavefunction that represents all possible paths it could take. The wavefunction at ... 09:56: ... action existed that was related to the integrated time evolution of the wavefunction. And he realized that this quantity should result in destructive ... 11:12: ... Schrodinger’s wave mechanics that talks about the evolution of a single wavefunction. This is analogous to how Lagrangian mechanics reproduced Newton’s ...
	2021-10-20: Will Constructor Theory REWRITE Physics? 12:30: ... in  Fact do particles even travel at all or do   their wave functions just randomly tunnel every  which way so that their ... 14:00: ... the particle itself is ever “inside the barrier”,   but its wavefunction certainly is inside the  barrier, and its wavefunction does seem ... 14:48: ... emergent   consequence of causality. If every particles  wavefunction is really spread over all of space   can anything really move ... 12:30: ... range of possible positions defined by  the spread of its position wavefunction, so if   you want to define tunneling as “the particle ... 14:00: ... the particle itself is ever “inside the barrier”,   but its wavefunction certainly is inside the  barrier, and its wavefunction does seem ... 14:48: ... emergent   consequence of causality. If every particles  wavefunction is really spread over all of space   can anything really move ... 12:30: ... for the particle to cross by   virtue of its own energy, its wavefunction drops  away exponentially. Tunneling is explicitly   defined as ...
	2021-10-13: New Results in Quantum Tunneling vs. The Speed of Light 02:46: It’s an abstract wave that encodes the information of where the proton might be. 08:50: ... study also finds that the tunneling wave packet isn’t necessarily “reshaped” all that much - it’s not clear that ... 02:41: We represent the location of, say, a proton in a nucleus as a wavefunction. 02:52: ... with another particle, the proton can end up anywhere within that wavefunction, with some locations more likely than ... 03:01: ... when a proton bounces around inside a nucleus, we need to see how its wavefunction evolves according the the Schrodinger equation - which is just the ... 03:13: This equation tells us that the wavefunction is mostly reflected or scattered back by the wall of the nucleus. 03:26: Due to the blurred-out nature of the wavefunction, a small part of it leaks out through to the other side. 03:37: Now the latter is very improbable - only as likely as the tiny fraction of the wavefunction that peaks through that barrier. 05:56: It seems natural to define those times as whenever the center of the wavefunction passes the start and end points. 06:01: But what if the wavefunction changes during the tunneling. 06:06: In a sense, the leading edge of the old wavefunction becomes the center of the new wavefunction. 06:45: It’s hard to measure the travel time of a quantum train OR a quantum wavefunction because it’s hard to define the start and end points. 07:01: Launch a particle through empty space with a well defined starting position, and it’s position wavefunction will spread out before the finish line. 07:08: ... center of that wavefunction can’t travel faster than the speed of light, but upon measurement, the ... 08:50: ... all that much - it’s not clear that we can really think of the new wavefunction as the cut-off front end of the old wavefunction, or the first carriage ... 13:59: ... through solid bedrock so there’s a low probability that your quantum wavefunction will make it through - but if you do then the trip is instantaneous, and ... 02:41: We represent the location of, say, a proton in a nucleus as a wavefunction. 02:52: ... with another particle, the proton can end up anywhere within that wavefunction, with some locations more likely than ... 03:01: ... when a proton bounces around inside a nucleus, we need to see how its wavefunction evolves according the the Schrodinger equation - which is just the ... 03:13: This equation tells us that the wavefunction is mostly reflected or scattered back by the wall of the nucleus. 03:26: Due to the blurred-out nature of the wavefunction, a small part of it leaks out through to the other side. 03:37: Now the latter is very improbable - only as likely as the tiny fraction of the wavefunction that peaks through that barrier. 05:56: It seems natural to define those times as whenever the center of the wavefunction passes the start and end points. 06:01: But what if the wavefunction changes during the tunneling. 06:06: In a sense, the leading edge of the old wavefunction becomes the center of the new wavefunction. 06:45: It’s hard to measure the travel time of a quantum train OR a quantum wavefunction because it’s hard to define the start and end points. 07:01: Launch a particle through empty space with a well defined starting position, and it’s position wavefunction will spread out before the finish line. 07:08: ... center of that wavefunction can’t travel faster than the speed of light, but upon measurement, the ... 08:50: ... all that much - it’s not clear that we can really think of the new wavefunction as the cut-off front end of the old wavefunction, or the first carriage ... 13:59: ... through solid bedrock so there’s a low probability that your quantum wavefunction will make it through - but if you do then the trip is instantaneous, and ... 07:08: ... measurement, the particle may appear to be at the leading edge of its wavefunction - potentially nudging it above light ... 03:01: ... when a proton bounces around inside a nucleus, we need to see how its wavefunction evolves according the the Schrodinger equation - which is just the equation of ... 05:56: It seems natural to define those times as whenever the center of the wavefunction passes the start and end points. 03:01: ... the the Schrodinger equation - which is just the equation of motion of wavefunctions. ...
	2021-10-05: Why Magnetic Monopoles SHOULD Exist 07:34: ... shift induced between the different sides of the string is exactly one wave cycle - which means no observable ... 04:37: ... are unaltered by changes in one simple property - the phase of the wavefunction. ... 06:52: In quantum mechanics, this works by shifting the phase of the particle’s wavefunction. 04:37: ... are unaltered by changes in one simple property - the phase of the wavefunction. ... 06:52: In quantum mechanics, this works by shifting the phase of the particle’s wavefunction.
	2021-09-21: How Electron Spin Makes Matter Possible 05:59: ... representing the position of a particle can look like a sine wave moving through space. If you have two such wavefunctions overlapping - ... 06:49: ... spinor wavefunction of the electron can “wave” through space, but it includes another wavy part. It has its rotational ... 05:59: ... - like two photons in a laser beam, a shift in one of them by half a wave cycle puts the two out of phase with each other. In that case they actually ... 06:49: ... wavy part. It has its rotational degree of freedom in which a full wave cycle is a 720 degree rotation. In that case a 360 degree rotation puts a ... 05:59: ... - like two photons in a laser beam, a shift in one of them by half a wave cycle puts the two out of phase with each other. In that case they actually cancel ... 02:59: ... in the recent episode - but for now just know that it’s just the type of wavefunction that fermions have, and has this property that it returns to its ... 05:59: ... in the classical sense. They’re quantum objects described by a quantum wavefunction. A wavefunction is this thing that holds information about the ... 06:49: ... spinor wavefunction of the electron can “wave” through space, but it includes another wavy ... 07:22: ... degree rotation shifts their phase by a half cycle and adds a -1 to the wavefunction. But we also know from the belt trick analogy that swapping two spinors ... 08:37: ... excited state. We can think of these two electrons as having a shared wavefunction - a two-particle wavefunction we’ll call Psi(A,B) - which has two ... 09:08: ... are fermions, which means that if we swap their locations the wavefunction gets multiplied by -1. Electron A goes into the first excited state and ... 09:45: ... be indistinguishable from each other. But it seems like the two-particle wavefunction changes if we swap the particles. Doesn’t that give us a way to ... 10:32: ... see that, we need to see what this two-particle wavefunction looks like in terms of the individual wavefunctions of our two ... 11:10: ... two-particle wavefunction needs to be a combination of f and g covering all the possibilities - in ... 11:21: ... it because it works. To prove it, let’s switch the particles and the wavefunction sign should flip. We want Psi(A,B) to become Psi(B,A). And Psi(B,A) is ... 12:04: ... swapping electrons flips the sign - so we’ve successfully discovered the wavefunction for a pair of ... 12:31: The two particle wavefunction would then look like this. The fs become gs. 13:03: ... saw from the belt-trick previously about spinors having anti-symmetric wavefunctions, is the pauli exclusion principle. That is, particles with half integer ... 13:25: ... rather more rigorous explanation of why spinors must have anti-symmetric wavefunctions that doesn’t involve pant-retention technology. It boils down to the ... 13:49: ... equation by itself doesn’t force you to use symmetric or anti-symmetric wavefunctions - but if you try to use the symmetric wavefunctions of the boson then ... 14:00: ... state of a particle forever. But if you use the correct anti-symmetric wavefunction then everything works just works out great. So it’s a proof by ... 02:59: ... in the recent episode - but for now just know that it’s just the type of wavefunction that fermions have, and has this property that it returns to its ... 05:59: ... in the classical sense. They’re quantum objects described by a quantum wavefunction. A wavefunction is this thing that holds information about the ... 06:49: ... spinor wavefunction of the electron can “wave” through space, but it includes another wavy ... 07:22: ... degree rotation shifts their phase by a half cycle and adds a -1 to the wavefunction. But we also know from the belt trick analogy that swapping two spinors ... 08:37: ... excited state. We can think of these two electrons as having a shared wavefunction - a two-particle wavefunction we’ll call Psi(A,B) - which has two ... 09:08: ... are fermions, which means that if we swap their locations the wavefunction gets multiplied by -1. Electron A goes into the first excited state and ... 09:45: ... be indistinguishable from each other. But it seems like the two-particle wavefunction changes if we swap the particles. Doesn’t that give us a way to ... 10:32: ... see that, we need to see what this two-particle wavefunction looks like in terms of the individual wavefunctions of our two ... 11:10: ... two-particle wavefunction needs to be a combination of f and g covering all the possibilities - in ... 11:21: ... it because it works. To prove it, let’s switch the particles and the wavefunction sign should flip. We want Psi(A,B) to become Psi(B,A). And Psi(B,A) is ... 12:04: ... swapping electrons flips the sign - so we’ve successfully discovered the wavefunction for a pair of ... 12:31: The two particle wavefunction would then look like this. The fs become gs. 14:00: ... state of a particle forever. But if you use the correct anti-symmetric wavefunction then everything works just works out great. So it’s a proof by ... 08:37: ... excited state. We can think of these two electrons as having a shared wavefunction - a two-particle wavefunction we’ll call Psi(A,B) - which has two ... 05:59: ... the probability of a given property being observed. For example, the wavefunction representing the position of a particle can look like a sine wave moving through ... 08:37: ... and one the first excited state. We’ll see what actually goes into this wavefunction shortly. ... 11:21: ... it because it works. To prove it, let’s switch the particles and the wavefunction sign should flip. We want Psi(A,B) to become Psi(B,A). And Psi(B,A) is just ... 05:59: ... can look like a sine wave moving through space. If you have two such wavefunctions overlapping - like two photons in a laser beam, a shift in one of them ... 09:08: ... state. So now we have Psi(B,A) and we know that Psi(A,B) = -Psi(B,A) Wavefunctions that change sign like this when it's particle labels are swapped are ... 10:32: ... this two-particle wavefunction looks like in terms of the individual wavefunctions of our two electrons. We’ll call the individual electron wavefunctions g ... 13:03: ... saw from the belt-trick previously about spinors having anti-symmetric wavefunctions, is the pauli exclusion principle. That is, particles with half integer ... 13:25: ... rather more rigorous explanation of why spinors must have anti-symmetric wavefunctions that doesn’t involve pant-retention technology. It boils down to the ... 13:49: ... equation by itself doesn’t force you to use symmetric or anti-symmetric wavefunctions - but if you try to use the symmetric wavefunctions of the boson then ... 10:32: ... and first excited state of the atom, but this works for any two possible wavefunctions - two possible quantum states - that our electrons could have. If electron ... 13:49: ... equation by itself doesn’t force you to use symmetric or anti-symmetric wavefunctions - but if you try to use the symmetric wavefunctions of the boson then you ... 09:08: ... sign are, unsurprisingly, called symmetric. Fermions have antisymmetric wavefunctions, bosons, ... 05:59: ... can look like a sine wave moving through space. If you have two such wavefunctions overlapping - like two photons in a laser beam, a shift in one of them by half a ...
	2021-09-15: Neutron Stars: The Most Extreme Objects in the Universe 10:06: ... making a very weak gravitational wave  signal. These gravitational waves are   much weaker than the signals we’ve detected when ... 08:15: ... are   outnumbered by neutrons 5 to 1. A given  neutron’s wavefunction is so spread out   that it becomes hard to even localize  ... 10:06: ... get dragged in circles,   making a very weak gravitational wave  signal. These gravitational waves are   much weaker than the ...
	2021-09-07: First Detection of Light from Behind a Black Hole 05:29: ... we’ve all experienced this Doppler shift when the sound waves of an ambulance siren shift between higher and lower pitch as it passes ... 02:41: A spectrum, by the way, is what you get when you split light into its component colors or wavelengths. 04:05: ... causing different parts of the disk to brighten - first the shorter wavelength which corresponds to the hot, inner disk, then to longer wavelengths of ... 05:15: In a normal spectrum we see the light from these electron transitions as sharp spikes at specific wavelengths - what we call emission lines. 05:22: But in a quasar, the gas is moving fast, and that motion shifts the wavelengths of the light as we see it. 07:33: Its light is blue-shifted to shorter wavelengths. 07:41: Meanwhile the gas closer to us is actually moving away from us as it falls towards the black hole - it’s redshifted to longer wavelengths. 10:22: We see that iron because it shines at a specific X-ray wavelength - this is the iron K-alpha line. 02:41: A spectrum, by the way, is what you get when you split light into its component colors or wavelengths. 04:05: ... wavelength which corresponds to the hot, inner disk, then to longer wavelengths of the cooler, outer ... 05:15: In a normal spectrum we see the light from these electron transitions as sharp spikes at specific wavelengths - what we call emission lines. 05:22: But in a quasar, the gas is moving fast, and that motion shifts the wavelengths of the light as we see it. 07:33: Its light is blue-shifted to shorter wavelengths. 07:41: Meanwhile the gas closer to us is actually moving away from us as it falls towards the black hole - it’s redshifted to longer wavelengths. 05:15: In a normal spectrum we see the light from these electron transitions as sharp spikes at specific wavelengths - what we call emission lines. 05:29: ... we’ve all experienced this Doppler shift when the sound waves of an ambulance siren shift between higher and lower pitch as it passes ...
	2021-08-18: How Vacuum Decay Would Destroy The Universe 01:31: ... rings, and so it can transfer its oscillations, causing a wave to propagate   through space. And there are other ways for ... 02:52: ... the field value is zero.   For example, for an electromagnetic wave  - a photon - the electric and magnetic   fields rise and fall ...
	2021-08-10: How to Communicate Across the Quantum Multiverse 00:23: ... your skull, that sound is nothing but an expanding series of density waves - air molecules mindlessly bumping and shoving each other, oblivious to ... 00:53: ... traffic. Each sound is its own configuration of overlapping sinusoidal waves. All these waves overlap to produce a fantastically complex bath of ... 01:46: ... brain filtered out all the others. The presence of those other sound waves has no impact on how my voice ... 02:29: ... point of measurement, leaving only one reality; or de Broglie-Bohm pilot wave theory, which says that particles are particles and waves are waves - ... 04:30: ... understand all of this, let’s first go back to sound waves. As we discussed in that previous episode, this ability for waves to pass ... 05:54: ... to be treated independently. A linear restoring force leads to a linear wave equation - and a linear wave equation is what you need for the ... 06:09: ... by too much. Non-linearities creep in which can do things like damp the waves - cause them to lose ... 05:54: ... to be treated independently. A linear restoring force leads to a linear wave equation - and a linear wave equation is what you need for the superposition ... 04:30: ... of multiple overlapping waves by calculating the evolution for each wave separately and then adding together the result. For that to be true, the medium ... 00:23: ... mindlessly bumping and shoving each other, oblivious to the complex wave structure that they propagate. And that sound wave itself can be deconstructed ... 02:29: ... point of measurement, leaving only one reality; or de Broglie-Bohm pilot wave theory, which says that particles are particles and waves are waves - and the ... 01:29: ... called the superposition principle. This principle also applies to the wavefunction in quantum ... 01:46: ... the Many Worlds interpretation of quantum mechanics, the universal wavefunction is the reality, encompassing all possible histories and futures and all ... 02:29: ... For example there’s the Copenhagen Interpretation, which says that the wavefunction collapses at the point of measurement, leaving only one reality; or de ... 03:30: ... Schrodinger equation describes how the wavefunction of a quantum system changes over space and time - and so it should ... 06:28: ... assumed that linearity and the superposition principle hold. Stack wavefunctions on top of each other and they behave as though the others aren’t there. ... 07:14: ... the Schrodinger equation would add extra non-linear observables to the wavefunction. The normal linear observables are things like position, momentum, spin - ... 09:57: ... that you choose to align the magnets. So your choice affects the quantum wavefunction. Polchinski lays out the steps very clearly: you send a spin half ... 11:05: First, you, but not other you, need to inject some information into the electron’s wavefunction. 11:11: ... perhaps impossible device that subjects both branches of the electron wavefunction to a non-linear field. That field sort of spreads the local information ... 12:00: ... that in a non-linear quantum mechanics, actions can influence the entire wavefunction - spanning different “worlds”. Perhaps real communication would be ... 01:29: ... called the superposition principle. This principle also applies to the wavefunction in quantum ... 01:46: ... the Many Worlds interpretation of quantum mechanics, the universal wavefunction is the reality, encompassing all possible histories and futures and all ... 02:29: ... For example there’s the Copenhagen Interpretation, which says that the wavefunction collapses at the point of measurement, leaving only one reality; or de ... 03:30: ... Schrodinger equation describes how the wavefunction of a quantum system changes over space and time - and so it should ... 07:14: ... the Schrodinger equation would add extra non-linear observables to the wavefunction. The normal linear observables are things like position, momentum, spin - ... 09:57: ... that you choose to align the magnets. So your choice affects the quantum wavefunction. Polchinski lays out the steps very clearly: you send a spin half ... 11:05: First, you, but not other you, need to inject some information into the electron’s wavefunction. 11:11: ... perhaps impossible device that subjects both branches of the electron wavefunction to a non-linear field. That field sort of spreads the local information ... 12:00: ... that in a non-linear quantum mechanics, actions can influence the entire wavefunction - spanning different “worlds”. Perhaps real communication would be ... 01:46: ... our world can happily do its thing unperturbed by other parts of the wavefunction - other “ripples”, or worlds. It’s as though you were only sensitive to ... 12:00: ... that in a non-linear quantum mechanics, actions can influence the entire wavefunction - spanning different “worlds”. Perhaps real communication would be ... 02:29: ... For example there’s the Copenhagen Interpretation, which says that the wavefunction collapses at the point of measurement, leaving only one reality; or de ... 11:11: ... information from each branch - each world - through the entire electron wavefunction. Finally, the electrons go back through the Stern-Gerlach device and other you ... 09:57: ... that you choose to align the magnets. So your choice affects the quantum wavefunction. Polchinski lays out the steps very clearly: you send a spin half particle like an ... 02:29: ... which says that particles are particles and waves are waves - and the wavefunction’s job is to shuttle actual real particles around - again, leading to one ... 06:28: ... assumed that linearity and the superposition principle hold. Stack wavefunctions on top of each other and they behave as though the others aren’t there. ... 02:29: ... which says that particles are particles and waves are waves - and the wavefunction’s job is to shuttle actual real particles around - again, leading to one ... 00:23: ... your skull, that sound is nothing but an expanding series of density waves - air molecules mindlessly bumping and shoving each other, oblivious to ... 00:53: ... traffic. Each sound is its own configuration of overlapping sinusoidal waves. All these waves overlap to produce a fantastically complex bath of ... 01:46: ... brain filtered out all the others. The presence of those other sound waves has no impact on how my voice ... 02:29: ... pilot wave theory, which says that particles are particles and waves are waves - and the wavefunction’s job is to shuttle actual real ... 04:30: ... understand all of this, let’s first go back to sound waves. As we discussed in that previous episode, this ability for waves to pass ... 06:09: ... by too much. Non-linearities creep in which can do things like damp the waves - cause them to lose ... 00:23: ... your skull, that sound is nothing but an expanding series of density waves - air molecules mindlessly bumping and shoving each other, oblivious to ... 02:29: ... pilot wave theory, which says that particles are particles and waves are waves - and the wavefunction’s job is to shuttle actual real particles around - ... 06:09: ... by too much. Non-linearities creep in which can do things like damp the waves - cause them to lose ... 00:23: ... your skull, that sound is nothing but an expanding series of density waves - air molecules mindlessly bumping and shoving each other, oblivious to the ... 00:53: ... is its own configuration of overlapping sinusoidal waves. All these waves overlap to produce a fantastically complex bath of density fluctuations. A ...
	2021-08-03: How An Extreme New Star Could Change All Cosmology 09:18: ... with black holes and neutron stars when LIGO detected the gravitational waves from the last moment of those inspirals. But it should happen with white ... 03:19: ... atom move between orbitals, they emit or absorb light with very specific wavelengths. That tells us what kind of atoms are in the object, but also a lot more. ... 09:18: ... with black holes and neutron stars when LIGO detected the gravitational waves from the last moment of those inspirals. But it should happen with white ...
	2021-07-21: How Magnetism Shapes The Universe 07:15: When radio waves interact with those electrons, their polarizations are also affected. 15:58: For example, particle position wavefunction is typically a smooth distribution of possible locations - some more probable than others. 16:18: To get this sort of splitting, two parts of that wavefunction need to influence other particles in ways that are distinguishable from each other. 16:49: ... that mean for the different weights - probabilities of those different wavefunction ... 17:42: One thing that will influence the number of worlds is if there’s any degree of suppression of the wavefunction. 17:49: For example, do the weakest, less “probable” parts of the wavefunction get pruned? 18:08: So Barefoot asks what if there’s a damping function that suppresses the universal wavefunction? 18:33: And anyway, as many of you pointed out - we don’t really need wavefunction damping if we have the time variance authority pruning worlds for us. 15:58: For example, particle position wavefunction is typically a smooth distribution of possible locations - some more probable than others. 16:18: To get this sort of splitting, two parts of that wavefunction need to influence other particles in ways that are distinguishable from each other. 16:49: ... that mean for the different weights - probabilities of those different wavefunction ... 17:42: One thing that will influence the number of worlds is if there’s any degree of suppression of the wavefunction. 17:49: For example, do the weakest, less “probable” parts of the wavefunction get pruned? 18:08: So Barefoot asks what if there’s a damping function that suppresses the universal wavefunction? 18:33: And anyway, as many of you pointed out - we don’t really need wavefunction damping if we have the time variance authority pruning worlds for us. 16:49: ... that mean for the different weights - probabilities of those different wavefunction branches? ... 18:33: And anyway, as many of you pointed out - we don’t really need wavefunction damping if we have the time variance authority pruning worlds for us. 07:15: When radio waves interact with those electrons, their polarizations are also affected.
	2021-07-13: Where Are The Worlds In Many Worlds? 01:47: ... wave mechanics, this principle tells us that when two waves overlap, their ... 02:09: Each ripple moves as though it’s the only wave on the pond. 02:25: The weirdness of this is clearer if we watch two waves cross each other in one dimension. 02:30: ... at their collision seems to hold no record of the shapes of the incoming waves, and yet its motion perfectly regenerates those waves, which travel on as ... 02:46: If the amplitude of the waves is is too high, the principle can break down. 03:06: The main point is that this holds approximately for familiar waves, up to some amplitude. 03:13: But the superposition principle seems to always hold for the waves that drive quantum mechanics. 03:39: Quantum mechanics is a theory about waves. 01:47: ... wave mechanics, this principle tells us that when two waves overlap, their amplitude - ... 03:20: ... the ability for the quantum wavefunction to co-exist and overlap without being affected by that overlap is how ... 03:42: It tells us that everything in the universe can be described by a wavefunction. 03:46: Where a pond ripple is an oscillation in surface height, the wavefunction is an oscillation in probability, or more accurately probability density. 04:04: ... appear to be randomly selected based on the current state of the wavefunction - more likely where the wavefunction is stronger, less where it’s ... 04:12: The wavefunction is what underlies our perceived reality. 04:16: We never see the wavefunction - we only see measurements - we pluck our reality from this fantastically complex structure. 04:23: ... array of possibilities, a sprinkling of the high points of the cosmic wavefunction. ... 04:32: The actual mechanics of quantum mechanics is all about determining the shape and evolution of the wavefunction. 04:38: To calculate this we use the Schrodinger equation, which tells us how the amplitude of the wavefunction changes over time and space. 04:46: Just as with our pond ripples, the wavefunction can overlap and either stack stack up or cancel out - constructive or destructive interference. 04:54: ... of this behavior is in the double-slit experiment, where the position wavefunction of an electron passes through two gaps in a screen and then interferes ... 05:06: ... on a detector screen, we find that we’re more likely to see it where the wavefunction is high - and so electron after electron we trace out these interference ... 05:22: ... of quantum mechanics - the Copenhagen Interpretation - tells us that the wavefunction “collapses” - it instantaneously shrinks from encompassing a huge range ... 05:53: It says that the wavefunction never collapses - it evolves forever by the Schrodinger equation. 05:59: The wavefunction of the electron joins the wavefunction of the detector screen at all points, rippling onwards. 06:09: What happens to the rest of its wavefunction? 06:11: ... understand that we have to remember that the electron’s wavefunction is only a tiny sliver of a great cosmic wavefunction that includes every ... 06:23: ... screen, what we’re really seeing is a cascade of ripples in the cosmic wavefunction, which encompasses the piece-wise wavefunctions of many particles as it ... 06:37: ... the wavefunction ripples through the detector, along wires, through computer circuitry, ... 06:54: The Copenhagen interpretation says that at some point in this process, most of the wavefunction vanishes. 07:00: ... to our observation of that spot cease to exist. Many Worlds says the wavefunction persists. It says that a cascade of ripples for every possible location ... 07:23: ... because the many, many interactions that these wavefunction branches experience on their way to your brain render them forever ... 07:51: But the key is that the wavefunction slice corresponding to those two worlds was still coherent. 07:57: ... still line up in a systematic way to produce high and low points in the wavefunction - meaningful blips in the probability ... 08:14: ... a perfectly reliable measurement without corrupting the phase of the wavefunction in a way that destroys coherence - destroys the relationship between ... 08:28: ... the detectors you still have two parts of the same electron’s wavefunction, but now the phase relationship, the correlation between peaks and ... 09:04: Once there’s no longer a recoverable phase relation between the branches of the wavefunction, the worlds have separated forever. 09:11: ... means the wavefunction of your brain also has branches - different internal states that ... 09:21: But those parts of your brain wavefunction are out of phase with each other. 10:05: After your visual cortex gets an image of the computer screen, a small slice of your brain's wavefunction splits in response to the possible results. 10:19: Ultimately your body’s position wavefunction splits - in one version you move left, in the other you move right. 11:02: Well, sort of - in the sense that the position wavefunctions of the two yous can be mapped to these spatial locations. 12:01: On a quantum scale, worlds - or wavefunction components - recombine all the time. 03:20: ... the ability for the quantum wavefunction to co-exist and overlap without being affected by that overlap is how ... 03:42: It tells us that everything in the universe can be described by a wavefunction. 03:46: Where a pond ripple is an oscillation in surface height, the wavefunction is an oscillation in probability, or more accurately probability density. 04:04: ... appear to be randomly selected based on the current state of the wavefunction - more likely where the wavefunction is stronger, less where it’s ... 04:12: The wavefunction is what underlies our perceived reality. 04:16: We never see the wavefunction - we only see measurements - we pluck our reality from this fantastically complex structure. 04:23: ... array of possibilities, a sprinkling of the high points of the cosmic wavefunction. ... 04:32: The actual mechanics of quantum mechanics is all about determining the shape and evolution of the wavefunction. 04:38: To calculate this we use the Schrodinger equation, which tells us how the amplitude of the wavefunction changes over time and space. 04:46: Just as with our pond ripples, the wavefunction can overlap and either stack stack up or cancel out - constructive or destructive interference. 04:54: ... of this behavior is in the double-slit experiment, where the position wavefunction of an electron passes through two gaps in a screen and then interferes ... 05:06: ... on a detector screen, we find that we’re more likely to see it where the wavefunction is high - and so electron after electron we trace out these interference ... 05:22: ... of quantum mechanics - the Copenhagen Interpretation - tells us that the wavefunction “collapses” - it instantaneously shrinks from encompassing a huge range ... 05:53: It says that the wavefunction never collapses - it evolves forever by the Schrodinger equation. 05:59: The wavefunction of the electron joins the wavefunction of the detector screen at all points, rippling onwards. 06:09: What happens to the rest of its wavefunction? 06:11: ... understand that we have to remember that the electron’s wavefunction is only a tiny sliver of a great cosmic wavefunction that includes every ... 06:23: ... screen, what we’re really seeing is a cascade of ripples in the cosmic wavefunction, which encompasses the piece-wise wavefunctions of many particles as it ... 06:37: ... the wavefunction ripples through the detector, along wires, through computer circuitry, ... 06:54: The Copenhagen interpretation says that at some point in this process, most of the wavefunction vanishes. 07:00: ... to our observation of that spot cease to exist. Many Worlds says the wavefunction persists. It says that a cascade of ripples for every possible location ... 07:23: ... because the many, many interactions that these wavefunction branches experience on their way to your brain render them forever ... 07:51: But the key is that the wavefunction slice corresponding to those two worlds was still coherent. 07:57: ... still line up in a systematic way to produce high and low points in the wavefunction - meaningful blips in the probability ... 08:14: ... a perfectly reliable measurement without corrupting the phase of the wavefunction in a way that destroys coherence - destroys the relationship between ... 08:28: ... the detectors you still have two parts of the same electron’s wavefunction, but now the phase relationship, the correlation between peaks and ... 09:04: Once there’s no longer a recoverable phase relation between the branches of the wavefunction, the worlds have separated forever. 09:11: ... means the wavefunction of your brain also has branches - different internal states that ... 09:21: But those parts of your brain wavefunction are out of phase with each other. 10:05: After your visual cortex gets an image of the computer screen, a small slice of your brain's wavefunction splits in response to the possible results. 10:19: Ultimately your body’s position wavefunction splits - in one version you move left, in the other you move right. 12:01: On a quantum scale, worlds - or wavefunction components - recombine all the time. 04:04: ... appear to be randomly selected based on the current state of the wavefunction - more likely where the wavefunction is stronger, less where it’s ... 04:16: We never see the wavefunction - we only see measurements - we pluck our reality from this fantastically complex structure. 07:57: ... still line up in a systematic way to produce high and low points in the wavefunction - meaningful blips in the probability ... 07:23: ... because the many, many interactions that these wavefunction branches experience on their way to your brain render them forever inaccessible ... 05:22: ... of quantum mechanics - the Copenhagen Interpretation - tells us that the wavefunction “collapses” - it instantaneously shrinks from encompassing a huge range of possible ... 12:01: On a quantum scale, worlds - or wavefunction components - recombine all the time. 07:00: ... to our observation of that spot cease to exist. Many Worlds says the wavefunction persists. It says that a cascade of ripples for every possible location on the ... 06:37: ... the wavefunction ripples through the detector, along wires, through computer circuitry, as ... 07:51: But the key is that the wavefunction slice corresponding to those two worlds was still coherent. 10:05: After your visual cortex gets an image of the computer screen, a small slice of your brain's wavefunction splits in response to the possible results. 10:19: Ultimately your body’s position wavefunction splits - in one version you move left, in the other you move right. 04:54: ... gaps in a screen and then interferes with itself to produce a complex wavefunction structure. ... 06:54: The Copenhagen interpretation says that at some point in this process, most of the wavefunction vanishes. 06:23: ... of ripples in the cosmic wavefunction, which encompasses the piece-wise wavefunctions of many particles as it makes its way to ... 08:14: ... destroys coherence - destroys the relationship between phases of the wavefunctions emerging from both ... 11:02: Well, sort of - in the sense that the position wavefunctions of the two yous can be mapped to these spatial locations. 08:14: ... destroys coherence - destroys the relationship between phases of the wavefunctions emerging from both ... 07:00: ... paths to the electron's wavefuntion not corresponding to our observation of that spot cease to exist. Many ... 01:47: ... wave mechanics, this principle tells us that when two waves overlap, their amplitude - in this case the height of the ripple - is ... 02:25: The weirdness of this is clearer if we watch two waves cross each other in one dimension. 02:30: ... at their collision seems to hold no record of the shapes of the incoming waves, and yet its motion perfectly regenerates those waves, which travel on as ... 02:46: If the amplitude of the waves is is too high, the principle can break down. 03:06: The main point is that this holds approximately for familiar waves, up to some amplitude. 03:13: But the superposition principle seems to always hold for the waves that drive quantum mechanics. 03:39: Quantum mechanics is a theory about waves. 02:25: The weirdness of this is clearer if we watch two waves cross each other in one dimension. 01:47: ... wave mechanics, this principle tells us that when two waves overlap, their amplitude - in this case the height of the ripple - is the sum of ...
	2021-07-07: Electrons DO NOT Spin 07:30: ... it did not include spin. Pauli managed to fix this by forcing the wavefunction to have two components - motivated by this  ambiguous ... 09:59: ... brings it back to normal. To get a little more technical - the spinor wavefunction has  a phase that changes with orientation angle - and a 360 ... 07:30: ... it did not include spin. Pauli managed to fix this by forcing the wavefunction to have two components - motivated by this  ambiguous ... 09:59: ... brings it back to normal. To get a little more technical - the spinor wavefunction has  a phase that changes with orientation angle - and a 360 ... 10:47: Meaning you can represent a particle wavefunction  in terms of either of these properties. 07:30: ... how quantum objects behave as evolving distributions of probability - as wavefunctions.It  was proving amazingly successful at describing some aspects of the ... 02:25: ... properties of electrons. That came from looking  at the specific wavelengths of photons emitted when electrons jump between energy levels  in ...
	2021-06-23: How Quantum Entanglement Creates Entropy 06:38: ... Quantum systems are described by what we call the wavefunction - that’s the distribution of   probabilities of all the ... 06:56: ... an example, imagine you have a quantum coin. It has a wavefunction that just   describes which side is up - heads or tails.  ... 07:44: ... about which way it would go wasn’t hidden in the unrevealed wavefunction. ... 09:22: ... and 50% tails heads. The von Neumann entropy of that entire wavefunction is still zero because   the combined wavefunction of the two ... 11:00: ... that it soon becomes impossible to access the entire   wavefunction. We call this process decoherence - it’s how the ordinary ... 11:50: ... become entangled with the coin and   live in the slice of the wavefunction - the mixed state -where the coin is either heads OR ... 06:38: ... Quantum systems are described by what we call the wavefunction - that’s the distribution of   probabilities of all the ... 06:56: ... an example, imagine you have a quantum coin. It has a wavefunction that just   describes which side is up - heads or tails.  ... 07:44: ... about which way it would go wasn’t hidden in the unrevealed wavefunction. ... 09:22: ... and 50% tails heads. The von Neumann entropy of that entire wavefunction is still zero because   the combined wavefunction of the two ... 11:00: ... that it soon becomes impossible to access the entire   wavefunction. We call this process decoherence - it’s how the ordinary ... 11:50: ... become entangled with the coin and   live in the slice of the wavefunction - the mixed state -where the coin is either heads OR ... 06:38: ... Quantum systems are described by what we call the wavefunction - that’s the distribution of   probabilities of all the possible ... 11:50: ... become entangled with the coin and   live in the slice of the wavefunction - the mixed state -where the coin is either heads OR ... 07:44: ... because its state is entirely   defined by its superposition wavefunction  - it is in a pure state of 50% heads 50%   tails. This is ... 09:22: ... - information IS hidden - it’s   hidden in the part of the wavefunction  corresponding to its entangled ... 07:44: ... because its state is entirely   defined by its superposition wavefunction  - it is in a pure state of 50% heads 50%   tails. This is subtly ... 09:22: ... - both possibilities   exist simultaneously. The unrevealed wavefunction is like this, which means 50% heads tails   and 50% tails heads. ... 08:42: ... tails before you reveal it. That  information of IS embedded in its wavefunction,   it just isn’t known to you. So the regular coin's entropy - in this ...
	2021-06-16: Can Space Be Infinitely Divided? 03:14: ... you can only clock the instant of the return to within one wave-cycle of the electromagnetic wave.   That gives a distance ... 03:47: ... Light carries energy and momentum - and the shorter the   wavelength, the more it carries. If you bombard your object with a powerful ... 04:30: ... momentum of the measured object,   and replace wavelength with uncertainty  in its position. Rearrange and voila,   ... 06:02: ... and who cares about   momentum. We keep decreasing the wavelength of our measuring photon - ultraviolet - X-ray -   ... 06:39: ... in the exact form as the Planck length  squared divided by the wavelength. ... 07:10: ... you pump up the energy of your photon,   reducing its wavelength also reduces the regular Heisenberg uncertainty, but at the same ... 07:48: ... a one-Planck-length   object. You need a photon with a  wavelength smaller than one-Planck-length.   But that photon has enough ... 06:02: ... and who cares about   momentum. We keep decreasing the wavelength of our measuring photon - ultraviolet - X-ray -   gamma-ray - which ... 07:48: ... a one-Planck-length   object. You need a photon with a  wavelength smaller than one-Planck-length.   But that photon has enough effective ... 04:30: ... photon’s momentum is the Planck  constant divided by its wavelength.   So just replace photon momentum with the uncertainty momentum of ... 06:39: ... and the energy of a photon is Planck’s  constant times c^2 over the wavelength.   We have this thing that’s full of our  wonderful fundamental ... 03:14: ... of the return to within one wave-cycle of the electromagnetic wave.   That gives a distance uncertainty of around one wavelength of ...
	2021-06-09: Are We Running Out of Space Above Earth? 00:00: ... of the Chinese Long March 5 rocket burning up on re-entry has made waves through the world- in some cases, quite literally, as the debris from ...
	2021-05-25: What If (Tiny) Black Holes Are Everywhere? 03:08: ... such black holes the Hawking radiation is just photons - electromagnetic waves with kilometers-long wavelengths, so really, really low energy radio ... 11:17: ... with the limits of the uncertainty principle in detecting gravitational waves. ... 13:36: ... can be gamed to improve measurements - in particular in gravitational wave ... 02:52: ... the wavelength of the emitted particles are about the size of the whole event horizon, ... 03:08: ... radiation is just photons - electromagnetic waves with kilometers-long wavelengths, so really, really low energy radio ... 03:25: But as the black hole shrinks in mass and in size, its Hawking radiation also decreases in wavelength - but it increases in energy. 05:13: In that motion they produce thermal radiation that includes every possible wavelength of light. 05:18: But if you zoom in on a single iron atom - it can’t emit every wavelength of light. 03:25: But as the black hole shrinks in mass and in size, its Hawking radiation also decreases in wavelength - but it increases in energy. 03:08: ... radiation is just photons - electromagnetic waves with kilometers-long wavelengths, so really, really low energy radio ... 11:17: ... with the limits of the uncertainty principle in detecting gravitational waves. ...
	2021-05-19: Breaking The Heisenberg Uncertainty Principle 00:25: ... And also pretty recently we have the measurement of gravitational waves by ... 02:05: That version is called matrix mechanics, but we get the same uncertainty principle using the wave mechanics of Schrodinger. 02:13: ... you can watch our episode on how it comes about from thinking about waves. ... 03:31: ... example, how can a quantum object sometimes be a “wave” and some times be a “particle?” In a sense it is both, and in a sense it ... 05:01: ... Laser Interferometer Gravitational Wave Observatory measures ripples in the fabric of space caused by ... 05:19: For fainter gravitational waves we quickly run up against the Heisenberg limit. 05:36: ... paths and then later recombined in such a way that the electromagnetic waves of these laser beams destructively ... 05:46: By that I mean that the peaks of one wave lines up with the troughs of the other, canceling out perfectly. 05:51: But if a gravitational wave passes through the interferometer, the relative lengths of the two paths change in a very particular way. 06:05: This measurement is incredibly sensitive to the path lengths - but that means it’s also sensitive to the phase of the light waves. 06:11: Phase refers to the relative positions of the peaks and troughs of the waves. 06:39: And that noise will obscure faint gravitational wave signals. 06:44: ... are larger than the change in the arm lengths due to a gravitational wave, then we’ll never see those ... 07:07: To improve our ability to detect faint gravitational waves we need to reduce the uncertainty in the phase of the laser beams. 07:15: That would enable us to line up those waves more perfectly to reduce quantum fluctuations. 09:05: Less flickering due to random phase shifts means that we can see real signals due to much weaker gravitational waves. 09:13: ... the next upgrade will allow them to detect up to 50% more gravitational wave events - events from further away, and involving lower-mass mergers of ... 09:43: But that noise is less of a problem than the phase uncertainty, at least for the higher frequency gravitational waves. 09:13: ... the next upgrade will allow them to detect up to 50% more gravitational wave events - events from further away, and involving lower-mass mergers of black ... 05:46: By that I mean that the peaks of one wave lines up with the troughs of the other, canceling out perfectly. 02:05: That version is called matrix mechanics, but we get the same uncertainty principle using the wave mechanics of Schrodinger. 05:01: ... Laser Interferometer Gravitational Wave Observatory measures ripples in the fabric of space caused by cataclysmic events up ... 05:51: But if a gravitational wave passes through the interferometer, the relative lengths of the two paths change in a very particular way. 06:39: And that noise will obscure faint gravitational wave signals. 00:25: ... And also pretty recently we have the measurement of gravitational waves by ... 02:13: ... you can watch our episode on how it comes about from thinking about waves. ... 05:19: For fainter gravitational waves we quickly run up against the Heisenberg limit. 05:36: ... paths and then later recombined in such a way that the electromagnetic waves of these laser beams destructively ... 06:05: This measurement is incredibly sensitive to the path lengths - but that means it’s also sensitive to the phase of the light waves. 06:11: Phase refers to the relative positions of the peaks and troughs of the waves. 07:07: To improve our ability to detect faint gravitational waves we need to reduce the uncertainty in the phase of the laser beams. 07:15: That would enable us to line up those waves more perfectly to reduce quantum fluctuations. 09:05: Less flickering due to random phase shifts means that we can see real signals due to much weaker gravitational waves. 09:43: But that noise is less of a problem than the phase uncertainty, at least for the higher frequency gravitational waves.
	2021-04-21: The NEW Warp Drive Possibilities 09:33: We can think of the warp field as a special type of isolated wave moving through space - what we call a soliton. 09:39: In previous work, this wave only waved in the direction of motion. 10:01: ... found that by including components of the wave motion that were perpendicular to the direction of motion he could build ... 12:47: And possibly also building a starship, to propel humanity into the galaxy on waves of warped space time. 10:01: ... found that by including components of the wave motion that were perpendicular to the direction of motion he could build a ... 09:33: We can think of the warp field as a special type of isolated wave moving through space - what we call a soliton. 09:39: In previous work, this wave only waved in the direction of motion. 12:47: And possibly also building a starship, to propel humanity into the galaxy on waves of warped space time.
	2021-03-23: Zeno's Paradox & The Quantum Zeno Effect 14:45: Max Graham asks how gravitational waves encode the distance that they've traveled. 15:08: But it's different with gravitational waves from merging black holes. 15:11: The intensity or amplitude of those waves drops off with distance, not distance squared. 15:16: But the important thing is that the amplitude of the wave is directly encoded in the frequency of the wave. 15:32: But that chirp mass also determines the power that was radiated in gravitational waves during the inspiral. 15:48: So then the amplitude of the wave as we see it at Earth tells us how much distance the wave must have traveled. 02:52: In the language of the Copenhagen interpretation of quantum mechanics, we say that the “wavefunction collapses” on observation. 02:58: ... as just the distribution of probability amplitudes of its position; its wavefunction is spread between the start and end of the ... 03:58: ... if there’s no observation the wavefunction evolves - less and less amplitude at the starting state and more and ... 04:15: ... your eyes for a second, which is your mistake - it allows the arrow’s wavefunction to evolve smoothly into the state of quantum ... 04:28: Every observation you make of the arrow collapses its wavefunction into one of its possible positions - start or end. 04:41: ... observation resets the trajectory to the start, at which point the wavefunction has to start evolving from scratch - but you keep observing it and keep ... 06:53: ... to the wavefunction collapse picture, it has to make a choice - the superposition must ... 07:23: In theory, if these “measurements” are fast enough they should stop the wavefunction from evolving. 08:43: ... what exactly do we mean by a “measurement” and what do we mean by wavefunction ... 09:55: ... idea is that measurement causes wavefunction collapse because it scrambles the delicate information connecting ... 10:04: Superposition only exists if the different parts of the wavefunction are connected or correlated with each other. 10:09: We would say that the wavefunction for different electron states or quantum arrow positions are in phase with each other, or “coherent”. 10:25: Decoherence occurs, and the different parts of the wavefunction, representing possible realities, can no longer interact. 10:38: ... to perfectly measure it, and that means decoherence - or the illusion of wavefunction ... 10:49: So on to wavefunction collapse. 10:52: In the Copenhagen interpretation, only the part of the wavefunction corresponding to the measurement outcome survives. 10:57: But in the Many Worlds interpretation, the entire wavefunction survives and splits and you split with it. 11:18: But in this case, you’re not forcing the wavefunction to collapse back to its starting position through the power of observation. 11:24: Your interaction with the wavefunction causes it to decohere - which means two things - you perturb the system in a non-subtle way. 12:15: And what is wavefunction collapse? 02:52: In the language of the Copenhagen interpretation of quantum mechanics, we say that the “wavefunction collapses” on observation. 02:58: ... as just the distribution of probability amplitudes of its position; its wavefunction is spread between the start and end of the ... 03:58: ... if there’s no observation the wavefunction evolves - less and less amplitude at the starting state and more and ... 04:15: ... your eyes for a second, which is your mistake - it allows the arrow’s wavefunction to evolve smoothly into the state of quantum ... 04:28: Every observation you make of the arrow collapses its wavefunction into one of its possible positions - start or end. 04:41: ... observation resets the trajectory to the start, at which point the wavefunction has to start evolving from scratch - but you keep observing it and keep ... 06:53: ... to the wavefunction collapse picture, it has to make a choice - the superposition must ... 07:23: In theory, if these “measurements” are fast enough they should stop the wavefunction from evolving. 08:43: ... what exactly do we mean by a “measurement” and what do we mean by wavefunction ... 09:55: ... idea is that measurement causes wavefunction collapse because it scrambles the delicate information connecting ... 10:04: Superposition only exists if the different parts of the wavefunction are connected or correlated with each other. 10:09: We would say that the wavefunction for different electron states or quantum arrow positions are in phase with each other, or “coherent”. 10:25: Decoherence occurs, and the different parts of the wavefunction, representing possible realities, can no longer interact. 10:38: ... to perfectly measure it, and that means decoherence - or the illusion of wavefunction ... 10:49: So on to wavefunction collapse. 10:52: In the Copenhagen interpretation, only the part of the wavefunction corresponding to the measurement outcome survives. 10:57: But in the Many Worlds interpretation, the entire wavefunction survives and splits and you split with it. 11:18: But in this case, you’re not forcing the wavefunction to collapse back to its starting position through the power of observation. 11:24: Your interaction with the wavefunction causes it to decohere - which means two things - you perturb the system in a non-subtle way. 12:15: And what is wavefunction collapse? 06:53: ... to the wavefunction collapse picture, it has to make a choice - the superposition must vanish and the ... 08:43: ... what exactly do we mean by a “measurement” and what do we mean by wavefunction collapse? ... 09:55: ... idea is that measurement causes wavefunction collapse because it scrambles the delicate information connecting different parts ... 10:38: ... to perfectly measure it, and that means decoherence - or the illusion of wavefunction collapse. ... 10:49: So on to wavefunction collapse. 12:15: And what is wavefunction collapse? 06:53: ... to the wavefunction collapse picture, it has to make a choice - the superposition must vanish and the electron ... 02:52: In the language of the Copenhagen interpretation of quantum mechanics, we say that the “wavefunction collapses” on observation. 03:58: ... if there’s no observation the wavefunction evolves - less and less amplitude at the starting state and more and more at the ... 10:25: Decoherence occurs, and the different parts of the wavefunction, representing possible realities, can no longer interact. 10:57: But in the Many Worlds interpretation, the entire wavefunction survives and splits and you split with it. 14:45: Max Graham asks how gravitational waves encode the distance that they've traveled. 15:08: But it's different with gravitational waves from merging black holes. 15:11: The intensity or amplitude of those waves drops off with distance, not distance squared. 15:32: But that chirp mass also determines the power that was radiated in gravitational waves during the inspiral. 15:11: The intensity or amplitude of those waves drops off with distance, not distance squared. 14:45: Max Graham asks how gravitational waves encode the distance that they've traveled.
	2021-03-16: The NEW Crisis in Cosmology 11:57: ... before too long we may even be able to use gravitational waves from merging black holes   to measure the Hubble constant. ... 15:19: ... the professor says that you just add   up the ripples of three waves. The student trolls the teacher with "what about four slits" which ... 01:16: ... us through the expanding universe it gets  stretched out - its wavelength increases.   If we also know how far that light traveled ... 11:57: ... before too long we may even be able to use gravitational waves from merging black holes   to measure the Hubble constant. ... 15:19: ... the professor says that you just add   up the ripples of three waves. The student trolls the teacher with "what about four slits" which ... 11:57: ... merging black holes   to measure the Hubble constant. These waves get stretched by the expanding universe, just like   light does. But unlike ... 15:19: ... slits" which they reply with "obviously you add up the ripples of four waves" And then "what about 5 slits" etc.. until finally   "what about ... 10:08: ... “baryon acoustic oscillations”  are the fossils of ancient sound waves   that reverberated through the hot, dense plasma of the early ... 15:19: ... you can figure out the interference pattern by thinking of circular waves   originating from the slits, and calculating how these ripples add ...
	2021-03-09: How Does Gravity Affect Light? 02:58: See, light is a wave. 03:00: The distance between the peaks of that wave is its wavelength. 07:31: Huygens’ wave theory of light advanced the field of optics enormously. 07:40: The idea is that any wave can be described as an infinite number of point-like oscillations, each of which produces new waves. 07:49: The sum of all those waves perfectly describes the future evolution of the original wave. 08:23: A plane wave of light is just an infinite number of new sources of light that generate the next step in the plane wave. 08:41: Our plane wave reaches the boundary to a new medium with a slower speed of light. 09:17: ... - first that light acts like a very classical, 17th-century style plane wave so you can use Huygens' ... 11:59: Light isn’t really a simple plane wave - it’s a much weirder quantum wave-particle thing. 12:32: Light is a wave and a particle; time slows or space flows in gravitational fields. 11:59: Light isn’t really a simple plane wave - it’s a much weirder quantum wave-particle thing. 08:41: Our plane wave reaches the boundary to a new medium with a slower speed of light. 07:31: Huygens’ wave theory of light advanced the field of optics enormously. 09:00: So now if we connect the wavelets to reconstruct the overall wavefront, we see that the path of the light has bent. 10:54: At each location perpendicular to a gravitational field, the wavefront of light can be thought of as a vertical column of new wavelets. 11:15: If you track the path of the wavefront by connecting the ripples, you see it bends. 03:00: The distance between the peaks of that wave is its wavelength. 03:18: Wavelength increases, which means frequency and energy drop. 04:10: These are the ticks of a clock, and the frequency dictates the frequency and the wavelength of the photon produced by that motion. 04:27: ... light emerging from it can be sapped of ALL energy - redshifted so the wavelength is effectively ... 03:18: Wavelength increases, which means frequency and energy drop. 07:58: At any point in time, the expanding ripple can be thought of as an infinite number of sources of new circular ripples, or wavelets. 08:07: Those wavelets also expand outwards, but they cancel each other out everywhere except in the outward direction of the original ripple. 08:47: ... it arrives at some angle, then the next set of wavelets forming at that boundary will be more closely packed - the fronts of ... 09:00: So now if we connect the wavelets to reconstruct the overall wavefront, we see that the path of the light has bent. 10:54: At each location perpendicular to a gravitational field, the wavefront of light can be thought of as a vertical column of new wavelets. 11:11: So those lower wavelets become bunched up from your perspective. 07:58: At any point in time, the expanding ripple can be thought of as an infinite number of sources of new circular ripples, or wavelets. 08:07: Those wavelets also expand outwards, but they cancel each other out everywhere except in the outward direction of the original ripple. 08:47: ... it arrives at some angle, then the next set of wavelets forming at that boundary will be more closely packed - the fronts of ... 09:00: So now if we connect the wavelets to reconstruct the overall wavefront, we see that the path of the light has bent. 10:54: At each location perpendicular to a gravitational field, the wavefront of light can be thought of as a vertical column of new wavelets. 11:11: So those lower wavelets become bunched up from your perspective. 08:47: ... it arrives at some angle, then the next set of wavelets forming at that boundary will be more closely packed - the fronts of those ... 11:59: Light isn’t really a simple plane wave - it’s a much weirder quantum wave-particle thing. 07:40: The idea is that any wave can be described as an infinite number of point-like oscillations, each of which produces new waves. 07:49: The sum of all those waves perfectly describes the future evolution of the original wave.
	2021-02-24: Does Time Cause Gravity? 08:39: Last time we talked about the gravitational wave background - the ambient buzz of gravitational waves from the distant and ancient universe. 09:10: ... I mentioned in reference to a potential component of the gravitational wave ... 10:04: ... the big bang, and gravitational Kinkusnacht asks whether gravitational waves can be used to test ideas in quantum ... 10:21: The most well known prospect is by detecting the signatures of primordial gravitational waves - waves from the inflationary epoch. 10:28: These could be found in the gravitational wave background, but also indirectly through their effect on the cosmic microwave background. 10:35: ... of those waves with matter right after inflation may have caused characteristic ... 08:39: Last time we talked about the gravitational wave background - the ambient buzz of gravitational waves from the distant and ancient universe. 09:10: ... I mentioned in reference to a potential component of the gravitational wave background. ... 10:28: These could be found in the gravitational wave background, but also indirectly through their effect on the cosmic microwave background. 08:39: Last time we talked about the gravitational wave background - the ambient buzz of gravitational waves from the distant and ancient universe. 10:04: ... the big bang, and gravitational Kinkusnacht asks whether gravitational waves can be used to test ideas in quantum ... 10:21: The most well known prospect is by detecting the signatures of primordial gravitational waves - waves from the inflationary epoch. 10:35: ... of those waves with matter right after inflation may have caused characteristic ... 10:21: The most well known prospect is by detecting the signatures of primordial gravitational waves - waves from the inflationary epoch.
	2021-02-17: Gravitational Wave Background Discovered? 00:00: ... impressive when we built this giant machine that spotted gravitational waves from colliding black holes well we've just taken it to the next level ...
	2021-02-10: How Does Gravity Warp the Flow of Time? 08:13: Now the worldline is.a sine wave.
	2021-01-19: Can We Break the Universe? 00:02: Black holes, gravitational waves, he was even the first to realize that friggin lasers could be a thing. 14:15: ... "true" is like asking if light is made up of particles or if light is a wave? ... 00:02: Black holes, gravitational waves, he was even the first to realize that friggin lasers could be a thing.
	2021-01-12: What Happens During a Quantum Jump? 04:45: He believed it all came down to waves—and that nothing was particularly special about these waves compared to any other kind of classical wave. 11:50: ... and Heisenberg in Copenhagen, or ride the continuous and deterministic wave of Schrodinger and ... 02:55: ... says that “measurement collapses the wavefunction”, which these days is more often taken to mean that interaction with the ... 03:07: But one guy was not impressed by this idea - the inventor of the wavefunction himself, Erwin Schrödinger. 10:54: ... the act of measuring a system will, in Copenhagen terms, collapse the wavefunction, which drastically changes how the system behaves - for example, trapping ... 02:55: ... says that “measurement collapses the wavefunction”, which these days is more often taken to mean that interaction with the ... 03:07: But one guy was not impressed by this idea - the inventor of the wavefunction himself, Erwin Schrödinger. 10:54: ... the act of measuring a system will, in Copenhagen terms, collapse the wavefunction, which drastically changes how the system behaves - for example, trapping ... 04:45: He believed it all came down to waves—and that nothing was particularly special about these waves compared to any other kind of classical wave.
	2020-12-15: The Supernova At The End of Time 14:24: And WE observers ride the wave of time in a particular direction. 14:28: If correlations grew in the opposite direction - the wave flowed backwards, our definition of future and past would flip. 15:25: ... after the measurement of particle position is made, the state of the wavefunction before that measurement is ... 15:38: ... the many worlds interpretation the wavefunction persists, so reversing time means reversing all outcomes of the ... 15:25: ... after the measurement of particle position is made, the state of the wavefunction before that measurement is ... 15:38: ... the many worlds interpretation the wavefunction persists, so reversing time means reversing all outcomes of the ...
	2020-12-08: Why Do You Remember The Past But Not The Future? 13:26: Yossi Sirote asks essentially the same question - doesn't the collapse of the wave function break time symmetry. 13:33: ... is that yes, IF quantum mechanics is fundamentally random, and IF the wavefunction collapse is a random rather than deterministic event, then time-reversal ... 13:47: ... and at any rate invoking random collapse doesn’t tell you why the wavefunction collapses in one direction and not the ... 13:33: ... is that yes, IF quantum mechanics is fundamentally random, and IF the wavefunction collapse is a random rather than deterministic event, then time-reversal ... 13:47: ... and at any rate invoking random collapse doesn’t tell you why the wavefunction collapses in one direction and not the ... 13:33: ... is that yes, IF quantum mechanics is fundamentally random, and IF the wavefunction collapse is a random rather than deterministic event, then time-reversal symmetry ... 13:47: ... and at any rate invoking random collapse doesn’t tell you why the wavefunction collapses in one direction and not the ...
	2020-11-11: Can Free Will be Saved in a Deterministic Universe? 05:52: The quantum information in the state of the wave function before collapse is destroyed, but information is also created. 06:04: Information threads both end and begin at every wave function collapse. 05:52: The quantum information in the state of the wave function before collapse is destroyed, but information is also created. 06:04: Information threads both end and begin at every wave function collapse.
	2020-11-04: Electroweak Theory and the Origin of the Fundamental Forces 05:07: Like all waves, the wavefunction has a phase - the current position of the peaks and troughs. 04:50: ... try an example: In quantum mechanics, the wavefunction determines the probabilities of certain outcomes being measured for ... 05:01: Quantum mechanical equations of motion like the Schrodinger equation describe how the wavefunction evolves through space and time. 05:07: Like all waves, the wavefunction has a phase - the current position of the peaks and troughs. 05:42: So there we go - we insisted on a symmetry - that the Schrodinger equation is invariant to changes in the local phase of the wavefunction. 06:05: ... shouldn’t change when we shift both the real and complex parts of the wavefunction by some amount, we shift the phase, a process which leaves the ... 06:20: ... not stretch or shrink: the length of the vector is the magnitude of the wavefunction, and the rotation amount is our local phase ... 06:57: ... can be completely represented by just one function, like our single wavefunction from the Schrodinger ... 04:50: ... try an example: In quantum mechanics, the wavefunction determines the probabilities of certain outcomes being measured for ... 05:01: Quantum mechanical equations of motion like the Schrodinger equation describe how the wavefunction evolves through space and time. 05:07: Like all waves, the wavefunction has a phase - the current position of the peaks and troughs. 05:42: So there we go - we insisted on a symmetry - that the Schrodinger equation is invariant to changes in the local phase of the wavefunction. 06:05: ... shouldn’t change when we shift both the real and complex parts of the wavefunction by some amount, we shift the phase, a process which leaves the ... 06:20: ... not stretch or shrink: the length of the vector is the magnitude of the wavefunction, and the rotation amount is our local phase ... 06:57: ... can be completely represented by just one function, like our single wavefunction from the Schrodinger ... 04:50: ... try an example: In quantum mechanics, the wavefunction determines the probabilities of certain outcomes being measured for observables ... 05:01: Quantum mechanical equations of motion like the Schrodinger equation describe how the wavefunction evolves through space and time. 06:05: ... we shift the phase, a process which leaves the magnitude of the wavefunction unchanged. ... 05:07: Like all waves, the wavefunction has a phase - the current position of the peaks and troughs.
	2020-10-27: How The Penrose Singularity Theorem Predicts The End of Space Time 13:38: ... equation. Other   interpretations - Copenhagen, pilot wave theory, etc. actually add things to the pure evolution   ...
	2020-10-20: Is The Future Predetermined By Quantum Mechanics? 02:46: According to quantum mechanics, physical systems, parts of the universe evolve as wave functions. 03:04: The wave function can be thought of as a state in which all physically possible realities intermingle. 03:21: The wave function is real. 04:03: At which point, the wave function collapses into a defined state. 04:23: ... wave function evolves in a precise way, perfectly defined by the equations of ... 04:36: The dice are thrown when the wave function collapses. 04:45: Another popular interpretation of quantum mechanics is the Many-Worlds Interpretation, which simply states that the wave function never collapses. 05:13: The wave function never collapses, it evolves deterministically forever. 05:17: The illusion of randomness is that we find ourselves in the one branch of the wave function, corresponding to the reality we perceive. 05:41: It's tempting to equate everything outside our past light cone with the unobserved wave function. 05:48: You can imagine that light cone sort of just plowing through the undefined universal wave function, collapsing it as it goes. 05:56: Or at least the parts of that wave function for which signals actually reach our awareness. 06:09: But now let's say we believe that other observers in the universe can also collapse the same universal wave function with their observations. 06:58: ... past, and if we believe in other observers there's no way to keep the wave function of your future from being collapsed before you get ... 07:12: Now, there are subtleties in this wave function collapse idea. 07:36: In that case, un-collapsed wave functions tend to exist only in microscopic pockets or in very special circumstances. 07:46: ... the only totally coherent way for a non-deterministic wave function collapse interpretation like Copenhagen, to give you an ... 08:08: Your light cone sweeps through the global wave function but it doesn't collapse that wave function, rather it selects from it. 10:14: The evolution of the wave function is deterministic. 10:18: ... means all future branching of the wave function of your present, by which I mean the entanglement network that ... 10:50: It's that part of the global wave function that you are connected to via entanglement and that shares your timestamp of now. 11:10: ... should make an honorable mention de Broglie-Bohm pilot wave theory, This is an entirely deterministic interpretation that doesn't ... 11:27: ... universe of pilot wave theory is really a block universe but unfortunately, no one has ... 03:04: The wave function can be thought of as a state in which all physically possible realities intermingle. 03:21: The wave function is real. 04:03: At which point, the wave function collapses into a defined state. 04:23: ... wave function evolves in a precise way, perfectly defined by the equations of quantum ... 04:36: The dice are thrown when the wave function collapses. 04:45: Another popular interpretation of quantum mechanics is the Many-Worlds Interpretation, which simply states that the wave function never collapses. 05:13: The wave function never collapses, it evolves deterministically forever. 05:17: The illusion of randomness is that we find ourselves in the one branch of the wave function, corresponding to the reality we perceive. 05:41: It's tempting to equate everything outside our past light cone with the unobserved wave function. 05:48: You can imagine that light cone sort of just plowing through the undefined universal wave function, collapsing it as it goes. 05:56: Or at least the parts of that wave function for which signals actually reach our awareness. 06:09: But now let's say we believe that other observers in the universe can also collapse the same universal wave function with their observations. 06:58: ... past, and if we believe in other observers there's no way to keep the wave function of your future from being collapsed before you get ... 07:12: Now, there are subtleties in this wave function collapse idea. 07:46: ... the only totally coherent way for a non-deterministic wave function collapse interpretation like Copenhagen, to give you an un-collapsed ... 08:08: Your light cone sweeps through the global wave function but it doesn't collapse that wave function, rather it selects from it. 10:14: The evolution of the wave function is deterministic. 10:18: ... means all future branching of the wave function of your present, by which I mean the entanglement network that you ... 10:50: It's that part of the global wave function that you are connected to via entanglement and that shares your timestamp of now. 11:10: ... interpretation that doesn't have multiple realities, just a wave function that guides particles in a perfectly determined way defined by Bohmiam ... 07:12: Now, there are subtleties in this wave function collapse idea. 07:46: ... the only totally coherent way for a non-deterministic wave function collapse interpretation like Copenhagen, to give you an un-collapsed future is if ... 04:03: At which point, the wave function collapses into a defined state. 04:36: The dice are thrown when the wave function collapses. 05:48: You can imagine that light cone sort of just plowing through the undefined universal wave function, collapsing it as it goes. 07:46: ... give you an un-collapsed future is if you are the only being doing the wave function collapsing let's move on to ... 04:23: ... wave function evolves in a precise way, perfectly defined by the equations of quantum ... 02:46: According to quantum mechanics, physical systems, parts of the universe evolve as wave functions. 07:36: In that case, un-collapsed wave functions tend to exist only in microscopic pockets or in very special circumstances. 11:10: ... should make an honorable mention de Broglie-Bohm pilot wave theory, This is an entirely deterministic interpretation that doesn't have ... 11:27: ... universe of pilot wave theory is really a block universe but unfortunately, no one has convincingly ...
	2020-10-13: Do the Past and Future Exist? 03:56: Our awareness of the universe rides this forward-moving wave of the present. 09:23: Imagine that the future is created as the wave of the present sweeping out the block universe. 09:29: But where is that wave?
	2020-10-05: Venus May Have Life! 02:22: ... of Venus appear to absorb the Sun’s light in a weird way - more short wavelength visible and UV light is sucked up than expected, leading to the yellow ... 03:58: This can be done at far infrared and submillimeter radio wavelengths where the star’s own glare doesn’t kill the signal. 04:07: One possible biosignature in this range is phosphine, which absorbs photons of around 1.1mm wavelength. 02:22: ... of Venus appear to absorb the Sun’s light in a weird way - more short wavelength visible and UV light is sucked up than expected, leading to the yellow colour of ... 03:58: This can be done at far infrared and submillimeter radio wavelengths where the star’s own glare doesn’t kill the signal.
	2020-09-28: Solving Quantum Cryptography 06:59: ... different computers, you’re processing in different parts of the quantum wavefunction - or in different parallel realities if you’re into the Many Worlds ... 07:51: But now the entire superposition - all elements of the wavefunction are related by the period of their repetition. 08:00: ... the correct one - essentially, you cause those incorrect parts of the wavefunction to destructively interfere, leaving the correct period ... 06:59: ... different computers, you’re processing in different parts of the quantum wavefunction - or in different parallel realities if you’re into the Many Worlds ... 07:51: But now the entire superposition - all elements of the wavefunction are related by the period of their repetition. 08:00: ... the correct one - essentially, you cause those incorrect parts of the wavefunction to destructively interfere, leaving the correct period ... 06:59: ... different computers, you’re processing in different parts of the quantum wavefunction - or in different parallel realities if you’re into the Many Worlds ...
	2020-09-21: Could Life Evolve Inside Stars? 14:01: ... any continuous, periodic function can be represented as a sum of sine waves of different ... 14:11: But then motion in a circle can be represented by 2 separate sine waves for displacement in the x-y directions. 14:19: ... arbitrarily complex orbital motion can be represented with enough sine wave pairs in a fourier series - which can also look like a series of ... 14:01: ... any continuous, periodic function can be represented as a sum of sine waves of different ... 14:11: But then motion in a circle can be represented by 2 separate sine waves for displacement in the x-y directions.
	2020-09-08: The Truth About Beauty in Physics 07:49: He sought to develop a quantum mechanical wave equation that agreed with Einstein’s special relativity. 09:30: And Maxwell’s equations, which parsimoniously unite electricity and magnetism but also predict the existence of electromagnetic waves - of light. 09:42: ... mirrors - but the resulting theory predicts black holes, gravitational waves, and even the big ... 07:49: He sought to develop a quantum mechanical wave equation that agreed with Einstein’s special relativity. 04:17: ... in time, space, angle, or something more abstract like the phase of the wavefunction. ... 11:30: His idea of introducing a new symmetry to space was translated to adding a new symmetry to the wavefunction in quantum mechanics. 04:17: ... in time, space, angle, or something more abstract like the phase of the wavefunction. ... 11:30: His idea of introducing a new symmetry to space was translated to adding a new symmetry to the wavefunction in quantum mechanics. 13:50: Basically, why do we see specific wavelengths missing from starlight due to electrons absorbing those wavelengths in atoms? 13:58: Shouldn't those same electrons then drop back down in energy level, emitting the same wavelengths they absorbed? 14:04: ... absolutely do - and in some cases you see extra light at those special wavelengths - what we call emission lines, in some cases less light - absorption ... 14:22: ... in question are between us and a source of light that's bright at all wavelengths, then we see absorption - that's because although those atoms to reemit ... 13:50: Basically, why do we see specific wavelengths missing from starlight due to electrons absorbing those wavelengths in atoms? 13:58: Shouldn't those same electrons then drop back down in energy level, emitting the same wavelengths they absorbed? 14:04: ... absolutely do - and in some cases you see extra light at those special wavelengths - what we call emission lines, in some cases less light - absorption ... 14:22: ... in question are between us and a source of light that's bright at all wavelengths, then we see absorption - that's because although those atoms to reemit ... 14:04: ... absolutely do - and in some cases you see extra light at those special wavelengths - what we call emission lines, in some cases less light - absorption ... 13:50: Basically, why do we see specific wavelengths missing from starlight due to electrons absorbing those wavelengths in atoms? 09:30: And Maxwell’s equations, which parsimoniously unite electricity and magnetism but also predict the existence of electromagnetic waves - of light. 09:42: ... mirrors - but the resulting theory predicts black holes, gravitational waves, and even the big ... 09:30: And Maxwell’s equations, which parsimoniously unite electricity and magnetism but also predict the existence of electromagnetic waves - of light.
	2020-08-17: How Stars Destroy Each Other 10:43: ... to our episode on this strange new observation by LIGO: gravitational waves from the merger of a black hole with ... something ... 12:44: ... then the universe should be very faintly humming with a gravitational wave background from the countless mergers than happened in the earlier ... 13:15: That's an easy one - in order to generate detectible gravitational waves, both objects need to be extremely compact. 13:22: The waves get generated when extreme masses spiral together at very small distances. 13:32: They are ripped apart before getting close enough to generate gravitational waves. 12:44: ... then the universe should be very faintly humming with a gravitational wave background from the countless mergers than happened in the earlier ... 02:45: But it can be found if you look a little off center for a spot of light that flares erratically from visible to X-ray wavelengths. 06:16: ... pulses - most brightly in radio light, but potentially at all wavelengths. ... 07:38: He observed these objects using visible wavelength of light - and found one object was indeed pulsing. 02:45: But it can be found if you look a little off center for a spot of light that flares erratically from visible to X-ray wavelengths. 06:16: ... pulses - most brightly in radio light, but potentially at all wavelengths. ... 10:43: ... to our episode on this strange new observation by LIGO: gravitational waves from the merger of a black hole with ... something ... 13:15: That's an easy one - in order to generate detectible gravitational waves, both objects need to be extremely compact. 13:22: The waves get generated when extreme masses spiral together at very small distances. 13:32: They are ripped apart before getting close enough to generate gravitational waves.
	2020-08-10: Theory of Everything Controversies: Livestream 00:00: ... have in the case of a photon you have the c in which the photon is a wave if you will and then you have the wave itself and you can say well i ...
	2020-07-28: What is a Theory of Everything: Livestream 00:00: ... of this theory from 100 years ago was this notion of gravitational waves and these were only verified experimentally just a few years ago so ...
	2020-07-20: The Boundary Between Black Holes & Neutron Stars 00:00: When we detected the very first gravitational wave, a new window was opened to the mysteries of the universe. 00:23: By now we’re becoming used to announcements that a new gravitational wave event has been detected. 00:38: ... the LIGO and VIRGO gravitational wave observatories spot event after event, the excitement is shifting from ... 01:53: We’ve done gravitational wave astronomy before, but this event is so mysterious we had to cover it. 02:18: ... passage of a gravitational wave causes extremely tiny changes in these arm lengths, which in turn causes ... 02:30: ... August 14 2019, a gravitational wave hit the LIGO and VIRGO observatories one after the other in close ... 11:01: With new gravitational wave events coming every week or two, we’re sure to see more of these sorts of mergers. 01:53: We’ve done gravitational wave astronomy before, but this event is so mysterious we had to cover it. 00:23: By now we’re becoming used to announcements that a new gravitational wave event has been detected. 11:01: With new gravitational wave events coming every week or two, we’re sure to see more of these sorts of mergers. 02:30: ... August 14 2019, a gravitational wave hit the LIGO and VIRGO observatories one after the other in close ... 00:38: ... the LIGO and VIRGO gravitational wave observatories spot event after event, the excitement is shifting from the ... 02:30: ... observatories one after the other in close succession, consistent with a wave traveling through the entire earth at the speed of ... 01:04: ... the shape of the gravitational waveform, and based on calculations using Einstein’s general theory of relativity, ... 02:44: ... the shape of the detected waveform, the masses of the merging objects were figured figured out as 23.2 and ...
	2020-06-30: Dissolving an Event Horizon 08:55: ... any rate, our observations of gravitational waves from colliding black holes and various other methods for estimate black ... 15:14: ... mentioned that in conformal cyclic cosmology, photons and gravitational waves can pass the boundary from universe end to new big bang, and so there ... 08:55: ... any rate, our observations of gravitational waves from colliding black holes and various other methods for estimate black ... 15:14: ... mentioned that in conformal cyclic cosmology, photons and gravitational waves can pass the boundary from universe end to new big bang, and so there ...
	2020-06-22: Building Black Holes in a Lab 00:16: ... into tiny spaces in quasars or X-ray binary systems. Gravitational waves that perfectly match our theoretical prediction for black hole mergers. ... 02:12: ... So what happens if another fish goes over the waterfall? Since sound waves are just vibrations propagating through a medium, if the medium is ... 04:45: ... of water decreases, the current accelerates while the speed of surface waves slows ... 04:55: At some point the flow is faster than the waves - and that’s your analog event horizon. 05:01: ... the flow is in the opposite direction to the waves this is actually an analog white hole. Other experiments use a ... 08:04: ... black holes can donate some of their rotational energy to particles or waves that pass close by. This is the Penrose process, and when the particle ... 08:58: ... captures all the action to great precision. On one side of the tank, a wave generator propagates waves across the surface where they pass across the ... 09:09: These waves are analogous to incoming particles. The waves are only 1 millimeter high, but superradiance can increase their height by as much as 10%. 08:58: ... captures all the action to great precision. On one side of the tank, a wave generator propagates waves across the surface where they pass across the ... 05:25: ... hole scattering the vibrational modes of the quantum fields that have wavelengths similar to the black hole’s event ... 00:16: ... into tiny spaces in quasars or X-ray binary systems. Gravitational waves that perfectly match our theoretical prediction for black hole mergers. ... 02:12: ... So what happens if another fish goes over the waterfall? Since sound waves are just vibrations propagating through a medium, if the medium is ... 04:45: ... of water decreases, the current accelerates while the speed of surface waves slows ... 04:55: At some point the flow is faster than the waves - and that’s your analog event horizon. 05:01: ... the flow is in the opposite direction to the waves this is actually an analog white hole. Other experiments use a ... 08:04: ... black holes can donate some of their rotational energy to particles or waves that pass close by. This is the Penrose process, and when the particle ... 08:58: ... to great precision. On one side of the tank, a wave generator propagates waves across the surface where they pass across the ... 09:09: These waves are analogous to incoming particles. The waves are only 1 millimeter high, but superradiance can increase their height by as much as 10%. 04:55: At some point the flow is faster than the waves - and that’s your analog event horizon. 04:45: ... of water decreases, the current accelerates while the speed of surface waves slows ...
	2020-06-15: What Happens After the Universe Ends? 14:02: It turns out that, as well as photons, gravitational waves should be able to pass between aeons.
	2020-05-27: Does Gravity Require Extra Dimensions? 04:32: ... fact we saw in a previous episode how a particular gravitational wave detection from LIGO seemed to rule out the possibility of extra spatial ...
	2020-05-11: How Luminiferous Aether Led to Relativity 02:33: ... the fluid dynamics of the aether. But Huygens is most famous for his wave theory of light. By thinking of light as a wave, he was able to build a ... 03:25: ... a wave on a string: each string segment moves up and down only, tugging on ... 04:06: ... of Huygens’ aetheric gravity. And Newton also opposed this whole wave theory for light business. Now Newton’s case is complicated - some of ... 05:08: ... versus Newton. Light as a wave versus a particle. Most accepted Newton - as most always did. This was ... 05:53: ... light experiences refraction and interference like a wave. Add to that the fact that in the 1860s, Maxwell’s equations predicted ... 06:48: ... classical waves travel at a constant speed relative to their medium. For example, sound ... 07:00: But hop in a jet plane and you can chase your own sound waves so they appear to stand still. 07:06: ... apparent velocity of an object - or a wave - depends in a simple way on the velocity and direction of motion of the ... 07:19: ... wanna hope Galilean relativity is right OK, so if light is a classical wave in some medium then we should see changes in the apparent speed of light ... 09:02: ... And this is exactly the method that LIGO uses to detect gravitational waves. ... 09:26: ... the relative speed of light along the two arms. That would cause the wave pattern in one arm to lag behind the other, leading to a similar shift ... 11:04: ... aether - at least, not one that resembled a classical medium for wave propagation. The speed of light appeared to be independent of the motion ... 07:06: ... apparent velocity of an object - or a wave - depends in a simple way on the velocity and direction of motion of the ... 05:53: ... light experiences refraction and interference like a wave. Add to that the fact that in the 1860s, Maxwell’s equations predicted that ... 09:26: ... the relative speed of light along the two arms. That would cause the wave pattern in one arm to lag behind the other, leading to a similar shift in the ... 11:04: ... aether - at least, not one that resembled a classical medium for wave propagation. The speed of light appeared to be independent of the motion of the ... 03:25: ... that propagates an energy pattern through some medium. So if light is a wave, surely it also needs a medium. For Huygens, that medium was also the ... 02:33: ... the fluid dynamics of the aether. But Huygens is most famous for his wave theory of light. By thinking of light as a wave, he was able to build a theory ... 04:06: ... of Huygens’ aetheric gravity. And Newton also opposed this whole wave theory for light business. Now Newton’s case is complicated - some of his early ... 05:08: ... versus Newton. Light as a wave versus a particle. Most accepted Newton - as most always did. This was until ... 09:02: ... in different places. Changes in length quite a bit smaller than a single wavelength of light would produce observable shifts in the fringe pattern. And this ... 03:25: ... while the segments themselves just oscillate in place. In sound waves, air molecules oscillate back and forth to propagate a pattern in the ... 04:06: ... own corpuscular theory of light - light as tiny particles rather than waves. ... 05:08: ... an interference pattern passing between a pair of slits, like water waves do. These bright bands are points on the screen where the waveforms of ... 05:53: ... that in the 1860s, Maxwell’s equations predicted that electromagnetic waves should travel at exactly the speed of … wait for it, light. It was ... 06:48: ... classical waves travel at a constant speed relative to their medium. For example, sound ... 07:00: But hop in a jet plane and you can chase your own sound waves so they appear to stand still. 09:02: ... And this is exactly the method that LIGO uses to detect gravitational waves. ... 03:25: ... and forth to propagate a pattern in the density of the air. All familiar waves - what we’ll call classical waves - are a chain reaction that propagates ... 06:48: ... classical waves travel at a constant speed relative to their medium. For example, sound waves ...
	2020-05-04: How We Know The Universe is Ancient 16:59: ... multiverse and how there are way more treats in other branches of the wavefunction. ... 01:35: ... incredible speeds, based on their Doppler shift - the lengthening of the wavelengths of their light due to their motion. Then Edwin Hubble figured out the ...
	2020-04-28: Space Time Livestream: Ask Matt Anything 00:00: ... of photons that are redshifted okay and the restrict of gravitational waves what happens to their energy well so the answer is there are a couple ...
	2020-04-14: Was the Milky Way a Quasar? 07:25: ... shock waves created by the supernovae from a starburst in the Milky Way could ...
	2020-03-24: How Black Holes Spin Space Time 01:01: ... told us that black holes are very real. We’ve seen the gravitational waves caused by their mergers, we’ve witnessed the havoc they wreak on their ...
	2020-03-16: How Do Quantum States Manifest In The Classical World? 08:44: ... electron and positron. The measurement hasn't actually happened yet. The wave function hasn't collapsed. Here’s more evidence, even with the ... 17:40: ... world interpretation handles the probabilistic interpretation of the wave function. And then goes on to correctly answer their own question - to ... 08:44: ... electron and positron. The measurement hasn't actually happened yet. The wave function hasn't collapsed. Here’s more evidence, even with the vertically-aligned ... 17:40: ... world interpretation handles the probabilistic interpretation of the wave function. And then goes on to correctly answer their own question - to paraphrase: ... 00:44: ... mechanics tells us that the atom’s wavefunction can be in a superposition of states - simultaneously decayed or not ... 05:32: ... how entanglement is connected to measurement and the collapse of the wavefunction. ... 09:56: ... so our atomic measurement device doesn’t “collapse the wavefunction.” It doesn't settle measurement basis. So where does that happen? In order ... 16:29: ... may be how our big bang happened. If so, then the never-ending global wavefunction of the Many worlds interpretation could indeed be a big-bang machine. On ... 17:40: ... whereas the Copenhagen interpretation states that only one branch of the wavefunction survives measurement, corresponding to one possible result of that ... 00:44: ... mechanics tells us that the atom’s wavefunction can be in a superposition of states - simultaneously decayed or not ... 05:32: ... how entanglement is connected to measurement and the collapse of the wavefunction. ... 09:56: ... so our atomic measurement device doesn’t “collapse the wavefunction.” It doesn't settle measurement basis. So where does that happen? In order ... 16:29: ... may be how our big bang happened. If so, then the never-ending global wavefunction of the Many worlds interpretation could indeed be a big-bang machine. On ... 17:40: ... whereas the Copenhagen interpretation states that only one branch of the wavefunction survives measurement, corresponding to one possible result of that ...
	2020-03-03: Does Quantum Immortality Save Schrödinger's Cat? 01:11: It only explains why separate branches of the wavefunction - separate “alternate histories” - stop being able to interact with each other. 01:29: ... example the Copenhagen interpretation, which says that the wavefunction branches that we don’t observe somehow vanish at the moment of ... 02:33: ... radioactive decay over a certain period of time - that means the quantum wavefunction of the atom splits equally - the atom is simultaneously decayed and not ... 02:49: So then surely the cat’s wavefunction splits too - into dead and alive. 02:55: According to Copenhagen, one of these results becomes “real” when the physicist opens the box, while the other branch of the wavefunction vanishes. 03:03: But in Many Worlds both branches continue forever - and the physicist’s wavefunction also splits into two - I guess into guilty and relieved. 03:13: ... no way for them to confirm the existence of the other branch of the wavefunction. ... 04:50: According to Copenhagen, all branches of the wavefunction besides “definitely dead” get cut off with ruthless efficiency almost all the time. 04:59: But that’s not true in Many Worlds - according to which all branches of the wavefunction persist. 05:04: ... even after trying this experiment even once, there’ll be a branch of the wavefunction where the physicist opens the box and crawls out, to the amazement of ... 05:31: Many Worlds, on the other hand, guarantees their survival in at least one branch of the quantum wavefunction. 06:57: ... even if some insanely rare branches of your wavefunction keep you alive beyond your years, I’d advise you to quit smoking and do ... 10:55: And to all of you - thanks for joining me on this wavefunction branch. 12:19: Well, Vampyricon answers this partically, saying that each observer will be on one decohered branch of the wavefunction. 12:46: ... make consistent observations, and who are unaware of observers on other wavefunction branches who make different ... 15:33: Some of you may recall that this is also the official salute to identify yourself as someone capable of seeing the wavefunction. 01:11: It only explains why separate branches of the wavefunction - separate “alternate histories” - stop being able to interact with each other. 01:29: ... example the Copenhagen interpretation, which says that the wavefunction branches that we don’t observe somehow vanish at the moment of ... 02:33: ... radioactive decay over a certain period of time - that means the quantum wavefunction of the atom splits equally - the atom is simultaneously decayed and not ... 02:49: So then surely the cat’s wavefunction splits too - into dead and alive. 02:55: According to Copenhagen, one of these results becomes “real” when the physicist opens the box, while the other branch of the wavefunction vanishes. 03:03: But in Many Worlds both branches continue forever - and the physicist’s wavefunction also splits into two - I guess into guilty and relieved. 03:13: ... no way for them to confirm the existence of the other branch of the wavefunction. ... 04:50: According to Copenhagen, all branches of the wavefunction besides “definitely dead” get cut off with ruthless efficiency almost all the time. 04:59: But that’s not true in Many Worlds - according to which all branches of the wavefunction persist. 05:04: ... even after trying this experiment even once, there’ll be a branch of the wavefunction where the physicist opens the box and crawls out, to the amazement of ... 05:31: Many Worlds, on the other hand, guarantees their survival in at least one branch of the quantum wavefunction. 06:57: ... even if some insanely rare branches of your wavefunction keep you alive beyond your years, I’d advise you to quit smoking and do ... 10:55: And to all of you - thanks for joining me on this wavefunction branch. 12:19: Well, Vampyricon answers this partically, saying that each observer will be on one decohered branch of the wavefunction. 12:46: ... make consistent observations, and who are unaware of observers on other wavefunction branches who make different ... 15:33: Some of you may recall that this is also the official salute to identify yourself as someone capable of seeing the wavefunction. 01:11: It only explains why separate branches of the wavefunction - separate “alternate histories” - stop being able to interact with each other. 10:55: And to all of you - thanks for joining me on this wavefunction branch. 01:29: ... example the Copenhagen interpretation, which says that the wavefunction branches that we don’t observe somehow vanish at the moment of ... 12:46: ... make consistent observations, and who are unaware of observers on other wavefunction branches who make different ... 04:59: But that’s not true in Many Worlds - according to which all branches of the wavefunction persist. 02:49: So then surely the cat’s wavefunction splits too - into dead and alive. 02:55: According to Copenhagen, one of these results becomes “real” when the physicist opens the box, while the other branch of the wavefunction vanishes.
	2020-02-24: How Decoherence Splits The Quantum Multiverse 03:11: ... general wave mechanics, we say that a set of waves are coherent if they match in ... 03:29: Laser light is an example of a coherent wave. 03:38: ... particle seems to pass through two slits simultaneously as a probability wave that ultimately “collapses” to leave it as a single position on a ... 04:36: In this case that mostly means these two paths - these wavefunction slices, which we can represent with simple sine waves. 04:44: ... the path lengths are the same, the peaks of one wave line up with the peaks of the other - the two waves are perfectly in ... 05:16: Here the peaks of one wave line up with the troughs of the other and the wavefunction completely cancels out. 07:25: - but only as long as the wave function defining those histories remains coherent. 11:21: Without a consistent wave offset it’s not possible to map an interference pattern. 07:25: - but only as long as the wave function defining those histories remains coherent. 03:11: ... general wave mechanics, we say that a set of waves are coherent if they match in frequency and ... 11:21: Without a consistent wave offset it’s not possible to map an interference pattern. 05:32: Here the path lengths differ by exactly one full wavecycle. 00:35: ... measurement problem - the question of why and where the blurry quantum wavefunction collapses into well-defined measurement ... 00:48: We focused on a simple question: does conscious observation of a quantum system cause the wavefunction to collapse? 01:03: The upshot is that more and more physicists think that consciousness - and even measurement - don’t directly cause wavefunction collapse. 01:16: The collapse itself may be an illusion, and the alternate histories that the wavefunction represents may continue forever. 01:41: ... to dip our toes and cover one aspect of it, by thinking in terms of the wavefunction. ... 01:52: ... quantum systems are described by this wavefunction thing - it’s the mathematical object that defines the distribution of ... 02:04: Wavefunctions evolve over time according to the Schrodinger equation, and that evolution tracks how the system’s properties might change. 02:13: Another way to think about it is that the time-dependent wavefunction maps all possible histories for the object. 02:50: But this only works if those alternate histories - those branches of the wavefunction - remain “coherent”. 03:38: ... interference pattern, which ultimately traces out the shape of the same wavefunction - the wavefunction of each independent ... 04:22: We can think of those paths as slices of the wavefunction that represent possible trajectories. 04:36: In this case that mostly means these two paths - these wavefunction slices, which we can represent with simple sine waves. 04:57: Because the wavefunction is amplified at that spot, there’s a high probability of the particle landing there. 05:16: Here the peaks of one wave line up with the troughs of the other and the wavefunction completely cancels out. 05:36: And so on - so we ultimately see this series of bands - lots of particles where the wavefunction is amplified, few where it’s canceled. 05:44: In general we can see an interference pattern if there is coherence between different parts of the photon wavefunction. 05:59: In this case, the phases match perfectly when the wavefunction leaves the slits - peaks and troughs come out at the same time. 06:21: So we have two parts of the wavefunction - two branches or alternate histories - that have a consistent phase relation between them. 06:28: In principle we can bring those parts of the wavefunction back together to cause interference. 07:30: ... both slits AND it reaches both points on the screen - as long the wavefunctions defining those outcomes remain ... 07:58: The part of the wavefunction - corresponding to a possible path of the photon - is now disturbed by those particles. 08:05: ... can think of that wavefunction slice as the “possible photon” being absorbed and reemitted by those ... 08:18: ... that emerging wavefunction can still interfere with itself - the random phase offset would just ... 08:58: From our perspective the wavefunction has lost coherence - decoherence has occurred. 09:11: Any measurement device must introduce some level of decoherence to the wavefunction before it reaches the screen. 09:18: ... decoherence hypothesis, it’s not really some magical effect whereby the wavefunction “knows” that it has been observed and so ... 09:35: Let’s now leave the slits alone and let the coherent photon wavefunction reach the screen again. 09:54: We can think about the photon wavefunction becoming mixed with the wavefunctions of the quantum particles along this chain. 10:16: But by now that wavefunction is getting pretty messy. 10:27: Phase differences get introduced between the different branches of the increasingly complex wavefunction. 10:38: Two branches of the wavefunction will represent histories where the photon landed in different locations. 11:07: ... that phase offset becomes less and less knowable the further the wavefunction advances, and the chaotic nature of the system also ensures that the ... 11:35: Ultimately, that expanding wavefunction includes the circuitry of the computer, and then the circuitry of your brain. 11:41: ... multiple alternate histories propagating from the original double slit wavefunction, but by now each of those wavefunction branches corresponds to a specific ... 11:57: ... result in the conscious awareness consistent with that one branch of the wavefunction - corresponding to a single location for the double-slit ... 12:10: At this point, as far as you’re concerned, the wavefunction has collapsed - decoherence has occurred. 12:16: ... actually, the original double-slit wavefunction may well continue to expand and complexify as it mixes with the ... 12:31: So you shouldn’t think of yourself as this gods-eye observer, capable of seeing the whole wavefunction and causing it to collapse. 12:39: Rather you are embedded within the wavefunction and see only a slice of it - a slice corresponding to a single history. 12:46: ... still interact with each other due to the coherence of that part of the wavefunction. ... 12:59: ... order to do quantum experiments we need to isolate a slice of the global wavefunction and maintain its coherence - we need to have information about the ... 13:26: And by environment I mean anything that isn’t as perfectly controlled as your tiny, isolated wavefunction slice. 14:12: Nor is it accepted that decoherence fully explains the measurement problem and wavefunction collapse. 14:19: ... Many Worlds interpretation of quantum mechanics, in which there is no wavefunction collapses at ... 14:33: The multiple branches of the wavefunction as it interacts on macroscopic scales. 14:38: ... visible to us, stranded as we are on a single branch of the universal wavefunction that itself contains so much more than our little, decohered slice of ... 00:35: ... measurement problem - the question of why and where the blurry quantum wavefunction collapses into well-defined measurement ... 00:48: We focused on a simple question: does conscious observation of a quantum system cause the wavefunction to collapse? 01:03: The upshot is that more and more physicists think that consciousness - and even measurement - don’t directly cause wavefunction collapse. 01:16: The collapse itself may be an illusion, and the alternate histories that the wavefunction represents may continue forever. 01:41: ... to dip our toes and cover one aspect of it, by thinking in terms of the wavefunction. ... 01:52: ... quantum systems are described by this wavefunction thing - it’s the mathematical object that defines the distribution of ... 02:13: Another way to think about it is that the time-dependent wavefunction maps all possible histories for the object. 02:50: But this only works if those alternate histories - those branches of the wavefunction - remain “coherent”. 03:38: ... interference pattern, which ultimately traces out the shape of the same wavefunction - the wavefunction of each independent ... 04:22: We can think of those paths as slices of the wavefunction that represent possible trajectories. 04:36: In this case that mostly means these two paths - these wavefunction slices, which we can represent with simple sine waves. 04:57: Because the wavefunction is amplified at that spot, there’s a high probability of the particle landing there. 05:16: Here the peaks of one wave line up with the troughs of the other and the wavefunction completely cancels out. 05:36: And so on - so we ultimately see this series of bands - lots of particles where the wavefunction is amplified, few where it’s canceled. 05:44: In general we can see an interference pattern if there is coherence between different parts of the photon wavefunction. 05:59: In this case, the phases match perfectly when the wavefunction leaves the slits - peaks and troughs come out at the same time. 06:21: So we have two parts of the wavefunction - two branches or alternate histories - that have a consistent phase relation between them. 06:28: In principle we can bring those parts of the wavefunction back together to cause interference. 07:58: The part of the wavefunction - corresponding to a possible path of the photon - is now disturbed by those particles. 08:05: ... can think of that wavefunction slice as the “possible photon” being absorbed and reemitted by those ... 08:18: ... that emerging wavefunction can still interfere with itself - the random phase offset would just ... 08:58: From our perspective the wavefunction has lost coherence - decoherence has occurred. 09:11: Any measurement device must introduce some level of decoherence to the wavefunction before it reaches the screen. 09:18: ... decoherence hypothesis, it’s not really some magical effect whereby the wavefunction “knows” that it has been observed and so ... 09:35: Let’s now leave the slits alone and let the coherent photon wavefunction reach the screen again. 09:54: We can think about the photon wavefunction becoming mixed with the wavefunctions of the quantum particles along this chain. 10:16: But by now that wavefunction is getting pretty messy. 10:27: Phase differences get introduced between the different branches of the increasingly complex wavefunction. 10:38: Two branches of the wavefunction will represent histories where the photon landed in different locations. 11:07: ... that phase offset becomes less and less knowable the further the wavefunction advances, and the chaotic nature of the system also ensures that the ... 11:35: Ultimately, that expanding wavefunction includes the circuitry of the computer, and then the circuitry of your brain. 11:41: ... multiple alternate histories propagating from the original double slit wavefunction, but by now each of those wavefunction branches corresponds to a specific ... 11:57: ... result in the conscious awareness consistent with that one branch of the wavefunction - corresponding to a single location for the double-slit ... 12:10: At this point, as far as you’re concerned, the wavefunction has collapsed - decoherence has occurred. 12:16: ... actually, the original double-slit wavefunction may well continue to expand and complexify as it mixes with the ... 12:31: So you shouldn’t think of yourself as this gods-eye observer, capable of seeing the whole wavefunction and causing it to collapse. 12:39: Rather you are embedded within the wavefunction and see only a slice of it - a slice corresponding to a single history. 12:46: ... still interact with each other due to the coherence of that part of the wavefunction. ... 12:59: ... order to do quantum experiments we need to isolate a slice of the global wavefunction and maintain its coherence - we need to have information about the ... 13:26: And by environment I mean anything that isn’t as perfectly controlled as your tiny, isolated wavefunction slice. 14:12: Nor is it accepted that decoherence fully explains the measurement problem and wavefunction collapse. 14:19: ... Many Worlds interpretation of quantum mechanics, in which there is no wavefunction collapses at ... 14:33: The multiple branches of the wavefunction as it interacts on macroscopic scales. 14:38: ... visible to us, stranded as we are on a single branch of the universal wavefunction that itself contains so much more than our little, decohered slice of ... 02:50: But this only works if those alternate histories - those branches of the wavefunction - remain “coherent”. 03:38: ... interference pattern, which ultimately traces out the shape of the same wavefunction - the wavefunction of each independent ... 06:21: So we have two parts of the wavefunction - two branches or alternate histories - that have a consistent phase relation between them. 07:58: The part of the wavefunction - corresponding to a possible path of the photon - is now disturbed by those particles. 11:57: ... result in the conscious awareness consistent with that one branch of the wavefunction - corresponding to a single location for the double-slit ... 02:50: But this only works if those alternate histories - those branches of the wavefunction - remain “coherent”. 11:07: ... that phase offset becomes less and less knowable the further the wavefunction advances, and the chaotic nature of the system also ensures that the phase offset ... 11:41: ... from the original double slit wavefunction, but by now each of those wavefunction branches corresponds to a specific configuration of matter and information - in ... 01:03: The upshot is that more and more physicists think that consciousness - and even measurement - don’t directly cause wavefunction collapse. 14:12: Nor is it accepted that decoherence fully explains the measurement problem and wavefunction collapse. 00:35: ... measurement problem - the question of why and where the blurry quantum wavefunction collapses into well-defined measurement ... 14:19: ... Many Worlds interpretation of quantum mechanics, in which there is no wavefunction collapses at ... 05:16: Here the peaks of one wave line up with the troughs of the other and the wavefunction completely cancels out. 11:35: Ultimately, that expanding wavefunction includes the circuitry of the computer, and then the circuitry of your brain. 05:59: In this case, the phases match perfectly when the wavefunction leaves the slits - peaks and troughs come out at the same time. 08:05: ... photon” being absorbed and reemitted by those particles, and so the wavefunction leaving that slit picks up a random phase offset compared to the other ... 02:13: Another way to think about it is that the time-dependent wavefunction maps all possible histories for the object. 09:35: Let’s now leave the slits alone and let the coherent photon wavefunction reach the screen again. 01:16: The collapse itself may be an illusion, and the alternate histories that the wavefunction represents may continue forever. 08:05: ... can think of that wavefunction slice as the “possible photon” being absorbed and reemitted by those ... 13:26: And by environment I mean anything that isn’t as perfectly controlled as your tiny, isolated wavefunction slice. 04:36: In this case that mostly means these two paths - these wavefunction slices, which we can represent with simple sine waves. 01:52: ... quantum systems are described by this wavefunction thing - it’s the mathematical object that defines the distribution of possible ... 02:04: Wavefunctions evolve over time according to the Schrodinger equation, and that evolution tracks how the system’s properties might change. 07:30: ... both slits AND it reaches both points on the screen - as long the wavefunctions defining those outcomes remain ... 09:54: We can think about the photon wavefunction becoming mixed with the wavefunctions of the quantum particles along this chain. 07:30: ... both slits AND it reaches both points on the screen - as long the wavefunctions defining those outcomes remain ... 02:04: Wavefunctions evolve over time according to the Schrodinger equation, and that evolution tracks how the system’s properties might change. 03:11: ... general wave mechanics, we say that a set of waves are coherent if they match in frequency and if the shape of the waves ... 04:36: In this case that mostly means these two paths - these wavefunction slices, which we can represent with simple sine waves. 04:44: ... the peaks of one wave line up with the peaks of the other - the two waves are perfectly in phase with each ...
	2020-02-18: Does Consciousness Influence Quantum Mechanics? 02:17: That’s the same pattern that would be produced by a wave passing through both slits - a so-called interference pattern. 02:31: Each solitary electron must know the entire wave pattern - which means it must, in some sense, travel through both slits. 02:40: ... saying that the electron does NOT travel as a particle or as a physical wave along one of these ... 02:51: Instead it travels as an abstract “probability wave” - something we call a wavefunction. 02:58: That probability wave defines the location of the electron at any point IF you try to measure it. 11:30: So what ... maybe one of you is forcing their preferred wave function collapse on everyone else? 02:51: Instead it travels as an abstract “probability wave” - something we call a wavefunction. 02:58: That probability wave defines the location of the electron at any point IF you try to measure it. 11:30: So what ... maybe one of you is forcing their preferred wave function collapse on everyone else? 02:17: That’s the same pattern that would be produced by a wave passing through both slits - a so-called interference pattern. 02:31: Each solitary electron must know the entire wave pattern - which means it must, in some sense, travel through both slits. 02:51: Instead it travels as an abstract “probability wave” - something we call a wavefunction. 03:16: Prior to measurement, it IS its wavefunction. 03:20: ... tells us that when we make that measurement the wavefunction “collapses” - it goes from a cloud of possible final destinations for ... 03:34: ... Wavefunction collapse seems essential because our large-scale, classical world isn’t ... 03:56: ... electron wavefunction passes through both slits, reaches the electronic detector, and there it ... 04:46: ... wrote that wavefunction collapse must happen somewhere between the measuring apparatus and the ... 04:56: Probably not as soon as our electron wavefunction reaches the detector. 05:05: That means the traveling electron’s wavefunction will just become mixed with the wavefunctions of all electrons that it could possibly excite. 05:14: ... should get what we call a superposition of states: a wavefunction in which an electron at every location on the detector screen is ... 05:27: So perhaps the wavefunction transition happens somewhere in the circuitry, or in the computer, or in the retina. 05:42: With no clear boundary between the quantum and the classical, where does the collapse of the wavefunction happen? 05:53: John von Neumann believed that wavefunction collapse must happen at the moment of conscious awareness of the result of an experiment. 06:12: ... idea that consciousness collapses the wavefunction is now called the von Neumann-Wigner interpretation, and it’s sort of a ... 07:26: They think you’re crazy - they tell you the wavefunction collapsed as soon as the physical experiment was completed. 07:38: So there’s the conflict - different observers say the wavefunction collapses at different times. 07:55: Therefore he concluded that conscious experience must itself must play a role in generating wavefunction collapse. 09:16: ... - like that you can influence reality by acts of will - collapse the wavefunction in your favour to force the location of a spot on a screen, or influence ... 10:41: ... Heisenberg’s later writing he states that the wavefunction collapse must be a continuous process between the measurement device and ... 11:24: You talk to each other and agree that you observed the same result - the wavefunction collapses in the same way for both of you. 12:00: ... you could talk about a global consciousness collapsing a universal wavefunction - but that’s not going to give you any powers of quantum ... 12:19: In fact there are some very precise explanations for why the wavefunction appears to collapse. 12:32: ... what happens to these multiple alternate histories after the electron wavefunction reaches the detector - and why these histories stop communicating with ... 12:49: ... now, one thing I can say with certainty is that your own future wavefunction includes a deeper dive into the quantum-classical divide, on an upcoming ... 02:51: Instead it travels as an abstract “probability wave” - something we call a wavefunction. 03:16: Prior to measurement, it IS its wavefunction. 03:20: ... tells us that when we make that measurement the wavefunction “collapses” - it goes from a cloud of possible final destinations for ... 03:34: ... Wavefunction collapse seems essential because our large-scale, classical world isn’t ... 03:56: ... electron wavefunction passes through both slits, reaches the electronic detector, and there it ... 04:46: ... wrote that wavefunction collapse must happen somewhere between the measuring apparatus and the ... 04:56: Probably not as soon as our electron wavefunction reaches the detector. 05:05: That means the traveling electron’s wavefunction will just become mixed with the wavefunctions of all electrons that it could possibly excite. 05:14: ... should get what we call a superposition of states: a wavefunction in which an electron at every location on the detector screen is ... 05:27: So perhaps the wavefunction transition happens somewhere in the circuitry, or in the computer, or in the retina. 05:42: With no clear boundary between the quantum and the classical, where does the collapse of the wavefunction happen? 05:53: John von Neumann believed that wavefunction collapse must happen at the moment of conscious awareness of the result of an experiment. 06:12: ... idea that consciousness collapses the wavefunction is now called the von Neumann-Wigner interpretation, and it’s sort of a ... 07:26: They think you’re crazy - they tell you the wavefunction collapsed as soon as the physical experiment was completed. 07:38: So there’s the conflict - different observers say the wavefunction collapses at different times. 07:55: Therefore he concluded that conscious experience must itself must play a role in generating wavefunction collapse. 09:16: ... - like that you can influence reality by acts of will - collapse the wavefunction in your favour to force the location of a spot on a screen, or influence ... 10:41: ... Heisenberg’s later writing he states that the wavefunction collapse must be a continuous process between the measurement device and ... 11:24: You talk to each other and agree that you observed the same result - the wavefunction collapses in the same way for both of you. 12:00: ... you could talk about a global consciousness collapsing a universal wavefunction - but that’s not going to give you any powers of quantum ... 12:19: In fact there are some very precise explanations for why the wavefunction appears to collapse. 12:32: ... what happens to these multiple alternate histories after the electron wavefunction reaches the detector - and why these histories stop communicating with ... 12:49: ... now, one thing I can say with certainty is that your own future wavefunction includes a deeper dive into the quantum-classical divide, on an upcoming ... 12:00: ... you could talk about a global consciousness collapsing a universal wavefunction - but that’s not going to give you any powers of quantum ... 12:19: In fact there are some very precise explanations for why the wavefunction appears to collapse. 03:34: ... Wavefunction collapse seems essential because our large-scale, classical world isn’t made of ... 04:46: ... wrote that wavefunction collapse must happen somewhere between the measuring apparatus and the conscious ... 05:53: John von Neumann believed that wavefunction collapse must happen at the moment of conscious awareness of the result of an experiment. 07:55: Therefore he concluded that conscious experience must itself must play a role in generating wavefunction collapse. 10:41: ... Heisenberg’s later writing he states that the wavefunction collapse must be a continuous process between the measurement device and the ... 07:26: They think you’re crazy - they tell you the wavefunction collapsed as soon as the physical experiment was completed. 03:20: ... tells us that when we make that measurement the wavefunction “collapses” - it goes from a cloud of possible final destinations for the electron ... 07:38: So there’s the conflict - different observers say the wavefunction collapses at different times. 11:24: You talk to each other and agree that you observed the same result - the wavefunction collapses in the same way for both of you. 03:20: ... tells us that when we make that measurement the wavefunction “collapses” - it goes from a cloud of possible final destinations for the electron to ... 05:42: With no clear boundary between the quantum and the classical, where does the collapse of the wavefunction happen? 12:49: ... now, one thing I can say with certainty is that your own future wavefunction includes a deeper dive into the quantum-classical divide, on an upcoming episode ... 03:56: ... electron wavefunction passes through both slits, reaches the electronic detector, and there it ... 04:56: Probably not as soon as our electron wavefunction reaches the detector. 12:32: ... what happens to these multiple alternate histories after the electron wavefunction reaches the detector - and why these histories stop communicating with each ... 05:27: So perhaps the wavefunction transition happens somewhere in the circuitry, or in the computer, or in the retina. 05:05: That means the traveling electron’s wavefunction will just become mixed with the wavefunctions of all electrons that it could possibly excite.
	2020-01-27: Hacking the Nature of Reality 01:08: ... representations of quantum mechanics soon followed - for example, the wave mechanics driven by the Schrodinger equation and Paul Dirac’s notation ... 14:50: Adam Wulg asks whether gas surrounding a pair of merging black holes might significantly affect the gravitational wave signature. 14:57: Well, the answer is that those waves would be affected - but not by much. 15:01: ... to merge faster, so that should increase the frequency of the those waves and to a lesser extend the actual shape of the ... 01:08: ... representations of quantum mechanics soon followed - for example, the wave mechanics driven by the Schrodinger equation and Paul Dirac’s notation ... 14:50: Adam Wulg asks whether gas surrounding a pair of merging black holes might significantly affect the gravitational wave signature. 14:57: Well, the answer is that those waves would be affected - but not by much. 15:01: ... to merge faster, so that should increase the frequency of the those waves and to a lesser extend the actual shape of the ...
	2020-01-13: How To Capture Black Holes 00:24: ... September 2015 the laser interferometer gravitational wave observatory - LIGO - detected its first gravitational wave from the ... 00:59: ... not so surprising. Einstein’s general relativity predicted gravitational waves and astrophysics predicted black hole mergers. When two very massive ... 08:50: ... could lead to a bright burst of light to accompany the gravitational waves. ... 09:53: ... the release of gravitational waves delivers a kick to the final black hole - a bit like the recoil of a ... 10:18: ... of the two LIGO and the VIRGO observatories locates a gravitational wave source to a pretty large blob on the sky, which will typically contain ... 10:40: ... we now have advanced follow-up systems in place. As soon as a candidate wave is detected, multiple telescopes scan that region of the sky to search ... 11:32: ... like I said: gravitational wave astronomy will reveal many cosmic mysteries and strange phenomena. Now ... 00:24: ... September 2015 the laser interferometer gravitational wave observatory - LIGO - detected its first gravitational wave from the merger of two ... 10:18: ... of the two LIGO and the VIRGO observatories locates a gravitational wave source to a pretty large blob on the sky, which will typically contain hundreds ... 10:40: ... of the active galaxies — a fading flash that is brightest at ultraviolet wavelengths. ... 00:24: ... new way we discover new things. When we figured out how to see in radio waves quasars and supernova remnants lit up the sky, When we learned to see in ... 00:59: ... not so surprising. Einstein’s general relativity predicted gravitational waves and astrophysics predicted black hole mergers. When two very massive ... 08:50: ... could lead to a bright burst of light to accompany the gravitational waves. ... 09:53: ... the release of gravitational waves delivers a kick to the final black hole - a bit like the recoil of a ... 00:59: ... holes whip the fabric of space into expanding ripples - gravitational waves - which saps orbital energy from the system. The black holes spiral closer ... 09:53: ... may be visible to telescopes on Earth right after the gravitational waves arrive. ... 00:59: ... they coalesce into a single black hole, and the powerful gravitational waves produced in the last fraction of a second are what LIGO detects - sometimes from ... 00:24: ... new way we discover new things. When we figured out how to see in radio waves quasars and supernova remnants lit up the sky, When we learned to see in ...
	2019-12-02: Is The Universe Finite? 01:25: ... episode how that speckled pattern is the frozen imprint of sound waves that reverberated through the first few hundred thousand years after the ...
	2019-11-04: Why We Might Be Alone in the Universe 13:37: ... to test Loop Quantum Gravity So LQG predicts that light of different wavelengths travels at very slightly different ... 14:00: ... if space is quantized on tiny scales, then we expect the very shortest wavelengths of light to be slightly perturbed by these quantum cells of space - sort ... 14:15: Wavelengths longer than this quantum scale can ignore this fragmentation and so travel at normal speed. 13:37: ... to test Loop Quantum Gravity So LQG predicts that light of different wavelengths travels at very slightly different ... 14:00: ... if space is quantized on tiny scales, then we expect the very shortest wavelengths of light to be slightly perturbed by these quantum cells of space - sort ... 14:15: Wavelengths longer than this quantum scale can ignore this fragmentation and so travel at normal speed. 13:37: ... to test Loop Quantum Gravity So LQG predicts that light of different wavelengths travels at very slightly different ...
	2019-10-15: Loop Quantum Gravity Explained 12:41: ... high-energy gamma rays travelling a wee bit slower than low energy radio waves due to the way they propagate through the graininess of a loop quantum ... 14:15: David Bennack likes the idea of gravitational lensing of gravitational waves. Well so do I, David. 14:38: ... is that it was just one black hole merger, but the gravitational wave from it was deflected by a galaxy or something on its way to us - it was ... 15:03: Gravitational waves should be lensed in the same way as light, so it's a plausible explanation. 15:22: Still, we'll probably see a lensed gravitational wave at some point. 16:16: ... if the fabric of space and time can be stretched and if can have waves, that means it must have a sort of elasticity and resistance to ... 01:58: Like actors on a stage, where the actors are particles and wavefunctions and fields and the stage is the coordinates of space and time. 04:00: Absent measurement, they exist in a fuzzy space of possibilities called a wavefunction. 04:06: In the first formulations of quantum mechanics, that wavefunction describes the distribution of possible positions and momenta of, say, a particle. 04:16: These can then be resolved into concrete, measured values by acting on the wavefunction with so-called position and momentum operators. 04:25: The wavefunction and operators are fundamentally tied to the coordinate system. 04:51: In quantum mechanics, time is treated completely separately to other variables - there is no “time wavefunction” or “time operator”. 04:00: Absent measurement, they exist in a fuzzy space of possibilities called a wavefunction. 04:06: In the first formulations of quantum mechanics, that wavefunction describes the distribution of possible positions and momenta of, say, a particle. 04:16: These can then be resolved into concrete, measured values by acting on the wavefunction with so-called position and momentum operators. 04:25: The wavefunction and operators are fundamentally tied to the coordinate system. 04:51: In quantum mechanics, time is treated completely separately to other variables - there is no “time wavefunction” or “time operator”. 04:06: In the first formulations of quantum mechanics, that wavefunction describes the distribution of possible positions and momenta of, say, a particle. 01:58: Like actors on a stage, where the actors are particles and wavefunctions and fields and the stage is the coordinates of space and time. 12:41: ... high-energy gamma rays travelling a wee bit slower than low energy radio waves due to the way they propagate through the graininess of a loop quantum ... 14:15: David Bennack likes the idea of gravitational lensing of gravitational waves. Well so do I, David. 15:03: Gravitational waves should be lensed in the same way as light, so it's a plausible explanation. 16:16: ... if the fabric of space and time can be stretched and if can have waves, that means it must have a sort of elasticity and resistance to ...
	2019-10-07: Black Hole Harmonics 00:14: And the rich harmonics of those vibrations, seen through gravitational waves, could hold the secrets to the nature of the fabric of spacetime itself. 01:08: ... to detect with the miraculous work of the LIGO and VIRGO gravitational wave ... 02:14: ... inspiralling black holes make powerful spacetime ripples – gravitational waves – which intensify as the black holes approach merger, only becoming ... 02:48: As those vibrations give up their energy – in this case to sound waves – the vibrations fade. The bell rings down. 03:12: In the latter cases we can describe a vibrating string as a series of standing sine waves of different frequencies, all happening at the same time. 03:56: In the case of the event horizon, or any spherical-ish surface, we break down the oscillations not into sine waves but into spherical harmonics. 04:05: ... are a set of functions pretty analogous to 2-D sine wave on the surface of a sphere, and each spherical harmonic can represent a ... 04:24: For a black hole, another way to think of its quasinormal modes is as a set of gravitational waves trapped in orbit around the black hole. 07:22: ... with much greater precision than if they’d just used the gravitational wave signal from the lead-up to the ... 07:41: So this sort of frequency analysis of gravitational waves is being called gravitational wave spectroscopy. 08:22: ... team analyzed the harmonics in the gravitational wave ring-down from this event and claim a likely detection of at least one ... 11:42: LIGO has a publicly available alert system so that astronomers can follow up gravitational wave detections with other telescopes. 12:41: So, long story short – the initial promise of LIGO and the first detection of gravitational waves really seems to be panning out. 12:49: Gravitational wave astronomy is now really a thing. 12:59: ... with the new subfield of gravitational wave spectroscopy, we can now listen to the harmonics of ringing black holes, ... 12:49: Gravitational wave astronomy is now really a thing. 11:42: LIGO has a publicly available alert system so that astronomers can follow up gravitational wave detections with other telescopes. 01:08: ... to detect with the miraculous work of the LIGO and VIRGO gravitational wave observatories. ... 08:22: ... team analyzed the harmonics in the gravitational wave ring-down from this event and claim a likely detection of at least one overtone – ... 07:22: ... with much greater precision than if they’d just used the gravitational wave signal from the lead-up to the ... 07:41: So this sort of frequency analysis of gravitational waves is being called gravitational wave spectroscopy. 12:59: ... with the new subfield of gravitational wave spectroscopy, we can now listen to the harmonics of ringing black holes, and through ... 06:34: ... the waveform was nicely simulated by spherical harmonic oscillations right from the ... 09:13: ... with the estimate that was previously obtained by analyzing the entire waveform but ignoring the ... 00:14: And the rich harmonics of those vibrations, seen through gravitational waves, could hold the secrets to the nature of the fabric of spacetime itself. 02:14: ... inspiralling black holes make powerful spacetime ripples – gravitational waves – which intensify as the black holes approach merger, only becoming ... 02:48: As those vibrations give up their energy – in this case to sound waves – the vibrations fade. The bell rings down. 03:12: In the latter cases we can describe a vibrating string as a series of standing sine waves of different frequencies, all happening at the same time. 03:56: In the case of the event horizon, or any spherical-ish surface, we break down the oscillations not into sine waves but into spherical harmonics. 04:24: For a black hole, another way to think of its quasinormal modes is as a set of gravitational waves trapped in orbit around the black hole. 07:41: So this sort of frequency analysis of gravitational waves is being called gravitational wave spectroscopy. 12:41: So, long story short – the initial promise of LIGO and the first detection of gravitational waves really seems to be panning out. 04:24: For a black hole, another way to think of its quasinormal modes is as a set of gravitational waves trapped in orbit around the black hole.
	2019-09-30: How Many Universes Are There? 10:12: But consider the wave of universes that formed one second after our own.
	2019-06-20: The Quasar from The Beginning of Time 03:22: Light is a wave and the wavelength of that wave determines the properties of light. 07:43: Look out for Physics Girl's exploration of gravitational waves at LIGO. 03:22: Light is a wave and the wavelength of that wave determines the properties of light. 04:01: ... distant light somewhat. Turbulence in the atmosphere causes incoming wavefronts of light to be warped, and it blurs our ... 03:22: Light is a wave and the wavelength of that wave determines the properties of light. 03:27: For example, visible light – the wavelength range that our eyes are sensitive to – spans only a tiny fraction of the spectrum. 03:34: That's why we create telescopes – the universe looks very, very different at different wavelengths. 04:53: ... spectrograph takes incoming light and breaks it into its component wavelengths, similar to a prism, and it records how much energy is received at each ... 05:12: ... traveling through the expanding universe sapped energy and stretched the wavelength of that light so that it was infrared by the time it reached the earth ... 06:24: ... same signature wavelengths used to measure redshift are also broadened due to the extreme speeds of ... 03:27: For example, visible light – the wavelength range that our eyes are sensitive to – spans only a tiny fraction of the spectrum. 03:34: That's why we create telescopes – the universe looks very, very different at different wavelengths. 04:53: ... spectrograph takes incoming light and breaks it into its component wavelengths, similar to a prism, and it records how much energy is received at each ... 06:24: ... same signature wavelengths used to measure redshift are also broadened due to the extreme speeds of ... 07:43: Look out for Physics Girl's exploration of gravitational waves at LIGO.
	2019-06-17: How Black Holes Kill Galaxies 14:07: or in the detailed shape of the gravitational wave signal before collision.
	2019-06-06: The Alchemy of Neutron Star Collisions 02:47: ... shot to prominence last year when the LIGO and Virgo gravitational wave Observatories spotted the space-time ripples from the merger of a pair ... 13:02: ... insinuations in the comments I'm sure we didn't collapse Grumpy's wavefunction - can't Has Cheezburger just by talking about it quantum mechanics ...
	2019-05-16: The Cosmic Dark Ages 05:45: ... its spin direction it either absorbs or emits a radio photon with a wavelength of 21cm. When the first stars ignited they heated the surrounding gas, ... 08:11: ... the second photon of interest. It’s the Lyman-alpha photon – one with a wavelength of exactly 121.57 nanometers. That’s a hard ultraviolet photon that can ... 08:36: ... has expanded slightly. Photons that were once at the Lyman-alpha wavelength have been redshifted to longer wavelength and are no longer threatened ... 09:21: ... light continues on its way towards us, but the universe keeps expanding. Wavelength by wavelength, photons get absorbed as they are shifted into the danger ... 10:10: ... or being blasted back out again. This is the redshifted Lyman-alpha wavelength – once hard-ultraviolet, but now infrared. Everything to the left of ... 08:36: ... no longer threatened with absorption. Meanwhile, more energetic, shorter wavelength photons get shifted into the danger zone – they get completely absorbed as the ... 09:21: ... on its way towards us, but the universe keeps expanding. Wavelength by wavelength, photons get absorbed as they are shifted into the danger zone of Lyman-alpha ...
	2019-05-09: Why Quantum Computing Requires Quantum Cryptography 04:52: Another example is the polarization of a photon, a quantum of electromagnetic wave. 04:58: Polarization defines the direction that its electric and magnetic fields … wave.
	2019-05-01: The Real Science of the EHT Black Hole 01:53: We can think of light from a very distant point as coming in a series or plane waves. 02:03: So they arrive at a different part of their wave cycle – there’s a phase difference between them. 10:17: ... cool fact is that, just like those gravitational wave signals from a couple of years ago, the black hole looks just like we ... 02:03: So they arrive at a different part of their wave cycle – there’s a phase difference between them. 10:17: ... cool fact is that, just like those gravitational wave signals from a couple of years ago, the black hole looks just like we predict ... 02:27: It resolves between two points on the sky if the separation between those points results in a relative phase shift of around one wavecycle. 01:58: A given wavefront will reach one telescope slightly before the other. 02:36: ... other words, the extra distance the wavefronts have to travel to reach the second telescope should be different for the ... 04:34: ... as an interferometer by literally matching the identical mm-separated wavefronts that reach these telescopes separated by thousands of ... 02:36: ... other words, the extra distance the wavefronts have to travel to reach the second telescope should be different for the ... 04:34: ... as an interferometer by literally matching the identical mm-separated wavefronts that reach these telescopes separated by thousands of ... 02:36: ... different points on the sky, and that difference should be of order one wavelength for maximum ... 02:51: ... separated by an angle that is the same as the ratio between the observed wavelength and the separation of the telescopes – also called the ... 03:03: The longer the baseline and the shorter the wavelength, the better the resolution. 03:08: ... ratio between wavelength and baseline is the same as the ratio between the size of the object ... 03:19: ... resolution of any telescope – it’s the diffraction limit – the observed wavelength divided by the diameter of the ... 03:50: ... you build an interferometer that spans the planet Earth the wavelength you need in order to get this resolution is around 1mm, which is around ... 07:43: Remember that the EHT observes radio light with a wavelength of around a millimeter. 07:52: That wavelength should be dominated by synchrotron radiation, not from the thermal radiation of the accretion disk. 03:19: ... resolution of any telescope – it’s the diffraction limit – the observed wavelength divided by the diameter of the ... 03:50: ... order to get this resolution is around 1mm, which is around the shortest wavelength radio ... 01:53: We can think of light from a very distant point as coming in a series or plane waves.
	2019-04-10: The Holographic Universe Explained 08:23: ... weird thing is that when you write the quantum wave equation for the gluon strand with length expressed as a separate ...
	2019-02-20: Secrets of the Cosmic Microwave Background 01:34: ... of matter right after the big bang which evolved as colossal sound waves reverberated through the first few hundred thousand years of the ... 02:05: ... of pressure Collapsing baryons rebounded producing an expanding sound wave That expanding shell was eventually frozen in place 380,000 years later ... 01:34: ... of matter right after the big bang which evolved as colossal sound waves reverberated through the first few hundred thousand years of the ... 02:05: ... single expanding shell of plasma is simplistic In reality these acoustic waves pulse in and out of their over-dense regions They oscillated And the ... 01:34: ... of matter right after the big bang which evolved as colossal sound waves reverberated through the first few hundred thousand years of the Universe's ...
	2019-02-07: Sound Waves from the Beginning of Time 01:22: They are the fossils of the first sound waves in the universe, imprinted on the distribution of galaxies on the sky. 02:54: Second: Light was able to exert an enormous pressure on this plasma, as we'll see that it'd lead to the production of colossal sound waves. 03:04: And third: Those sound waves travelled fast. 04:35: This resulted in an acoustic wave, a true sound wave in the form of an expanding shell of increased density. 05:49: As the wave of plasma and photons decoupled, light began to stream freely through the universe as the cosmic background radiation. 06:07: The wave of plasma-turned-gas essentially froze in its current state. 06:46: ... the expanding wave froze, both dark matter and baryons flowed together and consolidated the ... 07:40: In reality, the density waves sloshed inwards and outwards. 11:35: So, we know how far the acoustic wave should have travelled before being frozen by recombination. 12:39: I mean think about it. There are rings in the sky inscribed in galaxies, frozen echoes of the very first sound waves to reverberate across space-time. 06:46: ... the expanding wave froze, both dark matter and baryons flowed together and consolidated the new ... 02:09: Unbound electrons present a huge target to scatter any wavelength of light. 01:22: They are the fossils of the first sound waves in the universe, imprinted on the distribution of galaxies on the sky. 02:54: Second: Light was able to exert an enormous pressure on this plasma, as we'll see that it'd lead to the production of colossal sound waves. 03:04: And third: Those sound waves travelled fast. 07:40: In reality, the density waves sloshed inwards and outwards. 12:39: I mean think about it. There are rings in the sky inscribed in galaxies, frozen echoes of the very first sound waves to reverberate across space-time. 07:40: In reality, the density waves sloshed inwards and outwards. 03:04: And third: Those sound waves travelled fast.
	2019-01-24: The Crisis in Cosmology 08:16: ...really vast sound waves that rippled across the universe. 12:37: Independent methods, like using gravitational lensing, or gravitational waves,... 03:05: This is the lengthening of the wavelength of light from that galaxy,... 08:16: ...really vast sound waves that rippled across the universe. 12:37: Independent methods, like using gravitational lensing, or gravitational waves,...
	2019-01-16: Our Antimatter, Mirrored, Time-Reversed Universe 03:02: ... the other type KL is long-lived and has an odd CV state it's wave function gets multiplied by -1 on a CP transformation and that means ...
	2019-01-09: Are Dark Matter And Dark Energy The Same? 09:31: ... fact that sinusoidal solution is only valid for the bit of the sine wave where the universe is expanding from zero time – the big bang - slowing ...
	2018-12-20: Why String Theory is Wrong 08:17: These strings are vibrating with standing waves like guitar strings, and their energy also depends on the frequency of that vibration. 08:25: That frequency depends on the density of wave cycles on the string. 08:30: ... just the number of wave cycles around each coil, or the mode number divided by the radius. So, ... 08:25: That frequency depends on the density of wave cycles on the string. 08:30: ... just the number of wave cycles around each coil, or the mode number divided by the radius. So, there ... 08:17: These strings are vibrating with standing waves like guitar strings, and their energy also depends on the frequency of that vibration.
	2018-12-12: Quantum Physics in a Mirror Universe 00:02: ... shifts in space-time and even the rather abstract phase of the wave function in quantum mechanics so it might be surprising to learn that ...
	2018-11-14: Supersymmetric Particle Found? 14:54: Some of you recalled a recent episode in which we talked about a study of gravitational waves that appears to refute the idea of extra dimensions.
	2018-11-07: Why String Theory is Right 00:59: ... string theory are literal strands and loops that vibrate with standing waves simply by changing the vibrational mode and you get different particles ... 06:05: ... equations of motion and follow a standard recipe to turn them into wave equations with various quantum weirdness added in like the uncertainty ... 06:36: A while ago, we talked about Paul Dirac developed a wave equation for the electron that took into account Einstein's special theory of relativity. 08:11: So, we expect the phase of the quantum wave function to be a gauge symmetry of any quantum theory. 10:41: ... smooth out that surface mathematically and write a nice, simple quantum wave equation from the equations of motion, but only for 1D strings making a ... 06:36: A while ago, we talked about Paul Dirac developed a wave equation for the electron that took into account Einstein's special theory of relativity. 10:41: ... smooth out that surface mathematically and write a nice, simple quantum wave equation from the equations of motion, but only for 1D strings making a 2D world ... 06:05: ... equations of motion and follow a standard recipe to turn them into wave equations with various quantum weirdness added in like the uncertainty relation ... 08:11: So, we expect the phase of the quantum wave function to be a gauge symmetry of any quantum theory. 00:59: ... string theory are literal strands and loops that vibrate with standing waves simply by changing the vibrational mode and you get different particles ...
	2018-10-25: Will We Ever Find Alien Life? 04:26: ... observations revealed that the wavelength dependence of the dips is consistent with dust, so likely natural space ...
	2018-10-18: What are the Strings in String Theory? 05:35: The key is that strings can carry waves. 05:38: And if the string has ends or is tied in a loop, then a wave will end up overlapping with itself. 05:45: In that case, you get a standing wave. 05:48: Roughly speaking, when these traveling waves overlap each other, they can either stack up or cancel out, constructive or destructive interference. 05:57: Constructive interference only happens if the wavelength of the wave fits a neat number of times along the length of the string. 06:04: Then the phases of the overlapping wave match in the right way, and that wavelength/frequency of the wave is enhanced. 06:22: These resonant frequencies depend on the length of the string, also its tension, which defines wave velocity and so relates frequency to wavelength. 06:48: Niels Bohr came up with the first quantum model for electron orbits by thinking of them as ring-like standing waves around the hydrogen atom. 08:00: By the way, those vibrations, the standing waves, are not some abstract internal wave. 08:05: The strings are real physical strands, and the waves are wiggles in actual space. 05:57: Constructive interference only happens if the wavelength of the wave fits a neat number of times along the length of the string. 06:04: Then the phases of the overlapping wave match in the right way, and that wavelength/frequency of the wave is enhanced. 06:22: These resonant frequencies depend on the length of the string, also its tension, which defines wave velocity and so relates frequency to wavelength. 05:57: Constructive interference only happens if the wavelength of the wave fits a neat number of times along the length of the string. 06:22: These resonant frequencies depend on the length of the string, also its tension, which defines wave velocity and so relates frequency to wavelength. 06:04: Then the phases of the overlapping wave match in the right way, and that wavelength/frequency of the wave is enhanced. 05:35: The key is that strings can carry waves. 05:48: Roughly speaking, when these traveling waves overlap each other, they can either stack up or cancel out, constructive or destructive interference. 06:48: Niels Bohr came up with the first quantum model for electron orbits by thinking of them as ring-like standing waves around the hydrogen atom. 08:00: By the way, those vibrations, the standing waves, are not some abstract internal wave. 08:05: The strings are real physical strands, and the waves are wiggles in actual space. 05:48: Roughly speaking, when these traveling waves overlap each other, they can either stack up or cancel out, constructive or destructive interference.
	2018-10-10: Computing a Universe Simulation 12:07: ... week, we looked at an amazing new result in which gravitational waves were used to search for and rule out the existence of an extra spatial ... 12:21: Glenn Stern asks about the fact that the gravitational waves from this neutron star merger arrived two seconds before the light from the merger. 12:31: How then can we say that the gravitational waves and the light traveled at the same speed? 12:40: Those gravitational waves and that light traveled a crazy long distance, 40 megaparsecs or around 150 million light years. 13:10: That led to the radio emission arriving hours after the gravitational waves. 13:30: ... from the neutron star merger started slightly after the gravitational wave ... 13:41: The gravitational waves start to get strong before the neutron stars even make contact. 13:30: ... from the neutron star merger started slightly after the gravitational wave signal. ... 12:07: ... week, we looked at an amazing new result in which gravitational waves were used to search for and rule out the existence of an extra spatial ... 12:21: Glenn Stern asks about the fact that the gravitational waves from this neutron star merger arrived two seconds before the light from the merger. 12:31: How then can we say that the gravitational waves and the light traveled at the same speed? 12:40: Those gravitational waves and that light traveled a crazy long distance, 40 megaparsecs or around 150 million light years. 13:10: That led to the radio emission arriving hours after the gravitational waves. 13:41: The gravitational waves start to get strong before the neutron stars even make contact.
	2018-10-03: How to Detect Extra Dimensions 00:10: Fortunately, with the discovery of gravitational waves, we're now living in a science fiction future. 00:18: ... We may have mentioned once or twice that the new era of gravitational wave astronomy is going to open new windows to the universe and unlock many ... 00:59: The key to this breakthrough was the gravitational wave event observed in August of 2017, GW170817. 01:17: And the LIGO and Virgo gravitational wave observatories detected the resulting ripples. 01:29: The resulting kilonova is first observed in gravitational waves and then as a gamma ray burst. 01:35: In GW170817, the flash of gamma radiation arrived 1.7 seconds after the gravitational waves. 01:50: Among other things, this optical identification gave a completely independent measurement of the distance traveled by the gravitational waves. 08:37: Well, here's where we finally get back to our gravitational waves. 08:41: ... into this hypothetical extra spatial dimension, then gravitational waves should lose energy to that extra dimension as they travel through ... 09:02: In regular 3D space, gravitational waves drop in intensity proportional to just distance, not distance squared. 09:11: If space has four or more dimensions, then gravitational waves should drop off in intensity faster than you'd expect in three dimensions. 09:22: Just observe a gravitational wave and figure out how much its intensity dropped off over the distance traveled. 09:41: All you need is a billion-dollar network of gravitational wave detectors and a way to independently measure the distance the wave traveled. 09:58: ... us to measure its distance completely independently to the gravitational wave signal, something that's impossible with black hole ... 10:10: ... in order to determine how much intensity was lost by the gravitational wave, we need to know how intense it was when it started its ... 10:20: ... super convenient property of gravitational waves is that you can figure this out by looking at other properties of the ... 10:42: The gravitational wave lost the right amount of intensity for a 3-plus-1-dimensional space-time. 11:06: ... the way, comparison of the electromagnetic and gravitational wave arrival times also allowed us to verify that gravity really does travel ... 00:18: ... We may have mentioned once or twice that the new era of gravitational wave astronomy is going to open new windows to the universe and unlock many ... 10:20: ... namely, the masses of the merging objects and the frequency of the wave combined with our independent distance ... 09:41: All you need is a billion-dollar network of gravitational wave detectors and a way to independently measure the distance the wave traveled. 00:59: The key to this breakthrough was the gravitational wave event observed in August of 2017, GW170817. 10:42: The gravitational wave lost the right amount of intensity for a 3-plus-1-dimensional space-time. 01:17: And the LIGO and Virgo gravitational wave observatories detected the resulting ripples. 09:58: ... us to measure its distance completely independently to the gravitational wave signal, something that's impossible with black hole ... 09:41: All you need is a billion-dollar network of gravitational wave detectors and a way to independently measure the distance the wave traveled. 00:10: Fortunately, with the discovery of gravitational waves, we're now living in a science fiction future. 01:29: The resulting kilonova is first observed in gravitational waves and then as a gamma ray burst. 01:35: In GW170817, the flash of gamma radiation arrived 1.7 seconds after the gravitational waves. 01:50: Among other things, this optical identification gave a completely independent measurement of the distance traveled by the gravitational waves. 08:37: Well, here's where we finally get back to our gravitational waves. 08:41: ... into this hypothetical extra spatial dimension, then gravitational waves should lose energy to that extra dimension as they travel through ... 09:02: In regular 3D space, gravitational waves drop in intensity proportional to just distance, not distance squared. 09:11: If space has four or more dimensions, then gravitational waves should drop off in intensity faster than you'd expect in three dimensions. 10:20: ... super convenient property of gravitational waves is that you can figure this out by looking at other properties of the ... 09:02: In regular 3D space, gravitational waves drop in intensity proportional to just distance, not distance squared.
	2018-09-20: Quantum Gravity and the Hardest Problem in Physics 02:25: It describes particles as waves of infinite possibility whose observed properties are intrinsically uncertain. 02:41: That math started with the Schrodinger equation, which tracks these probability waves through space and time. 02:58: We already talked about how Paul Dirac fixed part of the problem with a relativistic wave equation for the electron. 07:01: ... know that for a particle to have a highly defined location, its position wave function needs to be constructed from a wide range of momentum wave ... 13:30: When two black holes merge, a lot of energy is pumped into gravitational waves. 02:58: We already talked about how Paul Dirac fixed part of the problem with a relativistic wave equation for the electron. 07:01: ... know that for a particle to have a highly defined location, its position wave function needs to be constructed from a wide range of momentum wave functions ... 02:25: It describes particles as waves of infinite possibility whose observed properties are intrinsically uncertain. 02:41: That math started with the Schrodinger equation, which tracks these probability waves through space and time. 13:30: When two black holes merge, a lot of energy is pumped into gravitational waves.
	2018-09-05: The Black Hole Entropy Enigma 00:53: Also, we've seen them in their gravitational effects on their surrounding space and in the gravitational waves caused when they merge. 06:22: If you merge two black holes, some of their mass gets converted to the energy radiated away in gravitational waves. 00:53: Also, we've seen them in their gravitational effects on their surrounding space and in the gravitational waves caused when they merge. 06:22: If you merge two black holes, some of their mass gets converted to the energy radiated away in gravitational waves. 00:53: Also, we've seen them in their gravitational effects on their surrounding space and in the gravitational waves caused when they merge.
	2018-08-30: Is There Life on Mars? 11:51: This is the same way we map the ocean, by analyzing radio waves reflected from layers below the surface.
	2018-08-23: How Will the Universe End? 15:43: All they have is their quantum wave function, which tells the probability of the particle's location, momentum, spin, direction, et cetera. 15:50: Now, we can think of a quantum wave function as having a size because it can be spread out over space. 16:03: If we know with 100% certainty the position of an electron, then the size of its quantum wave function becomes zero. 17:40: As for the little financial firm, yeah, I heard they were doing pretty well under the wave of banking deregulation of the '80s and '90s. 15:43: All they have is their quantum wave function, which tells the probability of the particle's location, momentum, spin, direction, et cetera. 15:50: Now, we can think of a quantum wave function as having a size because it can be spread out over space. 16:03: If we know with 100% certainty the position of an electron, then the size of its quantum wave function becomes zero.
	2018-08-15: Quantum Theory's Most Incredible Prediction 15:13: Another possible mechanism is through turbulence in waves generated by the rapid motion of magnetic fields.
	2018-08-01: How Close To The Sun Can Humanity Get? 04:08: Finally, it will detect radio waves from processes responsible for the acceleration of particles in the solar wind.
	2018-07-11: Quantum Invariance & The Origin of The Standard Model 02:35: ... describes the evolution of the wave function, which is the mathematical object that contains all the ... 02:44: We can never see the underlying wave function of, say, a particle. 02:54: The wave function can represent different observables and it determines the distribution of possible results of measurement of those observables. 03:02: In this episode, we'll be talking about the position wave function. 03:11: The square of the magnitude of this wave function tells us the probability distribution of a particle's position. 03:24: This step of squaring the wave function is called the Born rule. 03:36: Let's see what happens when we square the wave function. 03:47: It's no simple wave. 04:03: Phase is just the wave's current state in its up-down oscillation. 04:07: When we apply the Born rule, what we're doing is squaring these two waves and adding them together. 04:40: In fact, as long as you make the same shift across the entire wave function, all the observables are unchanged. 05:21: We'll try this because, well, we already know that the magnitude squared of the wave function should still stay the same under local phase shifts. 05:38: ... here, only that location changes, as if it were part of the shifted wave, making a discontinuous ... 05:50: If you allow this sort of local phase shift, you can change each point in a different way and really mess up the wave function. 06:15: See, momentum is related to the average steepness of the wave function. 06:19: Change the shape of that wave function with local phase shifts and you actually break conservation of momentum. 06:57: ... that's specially designed to undo any mess we make to the phase of the wave ... 02:35: ... describes the evolution of the wave function, which is the mathematical object that contains all the information about ... 02:44: We can never see the underlying wave function of, say, a particle. 02:54: The wave function can represent different observables and it determines the distribution of possible results of measurement of those observables. 03:02: In this episode, we'll be talking about the position wave function. 03:11: The square of the magnitude of this wave function tells us the probability distribution of a particle's position. 03:24: This step of squaring the wave function is called the Born rule. 03:36: Let's see what happens when we square the wave function. 04:40: In fact, as long as you make the same shift across the entire wave function, all the observables are unchanged. 05:21: We'll try this because, well, we already know that the magnitude squared of the wave function should still stay the same under local phase shifts. 05:50: If you allow this sort of local phase shift, you can change each point in a different way and really mess up the wave function. 06:15: See, momentum is related to the average steepness of the wave function. 06:19: Change the shape of that wave function with local phase shifts and you actually break conservation of momentum. 06:57: ... that's specially designed to undo any mess we make to the phase of the wave function. ... 03:11: The square of the magnitude of this wave function tells us the probability distribution of a particle's position. 05:38: ... here, only that location changes, as if it were part of the shifted wave, making a discontinuous ... 04:03: Phase is just the wave's current state in its up-down oscillation. 04:07: When we apply the Born rule, what we're doing is squaring these two waves and adding them together. 04:03: Phase is just the wave's current state in its up-down oscillation.
	2018-06-13: What Survives Inside A Black Hole? 13:06: ... wave function prescribes the probability of observing a given value for a ... 13:22: In the Copenhagen interpretation, the wave function collapses and unitarity is not preserved. 13:30: More likely is that the observer and the observation are a small part of a global wave function that continues to evolve in a unitary manner. 13:06: ... wave function prescribes the probability of observing a given value for a property ... 13:22: In the Copenhagen interpretation, the wave function collapses and unitarity is not preserved. 13:30: More likely is that the observer and the observation are a small part of a global wave function that continues to evolve in a unitary manner. 13:22: In the Copenhagen interpretation, the wave function collapses and unitarity is not preserved. 13:06: ... wave function prescribes the probability of observing a given value for a property when the ...
	2018-05-23: Why Quantum Information is Never Destroyed 04:51: The time dependent Schrodinger equation describes the time evolution of this thing called the wave function. 04:58: The wave function of a system fully describes all of its properties. 05:02: ... of all of its properties, which you can get by taking the square of the wave ... 05:10: ... example, the wave function of a particle encapsulates the probability that it will be ... 05:19: ... perfectly predicts both the past and future evolution of a given wave function in any given environment, or in quantum speak, in any given ... 05:36: ... principle, a given wave function in a given potential could mean the wave function of an ... 06:10: Remember that the wave function encapsulates the distribution of probabilities for a given property. 06:42: If this is true, and it must be, we say that the time evolution of the wave function is unitary. 08:12: That value seems to be chosen randomly based on the probability distribution encoded in the wave function. 08:29: Quantum information refers to the full information content of the wave function, not just what we measure. 08:35: And in principle, make enough measurements and you can extract all of the information from a wave function. 08:41: ... worth mentioning that the collapse of the wave function in the Copenhagen interpretation of quantum mechanics actually ... 08:50: ... that interpretation, the active measurement actually alters the entire wave function causing it to shrink down to the narrow range of possible ... 09:02: But that measured wave function can't then be tracked backwards to recover the past wave function. 09:14: ... for example, Everett's many-worlds or the de Broglie-Bohm pilot wave theory preserve this time ... 09:22: In the case of many-worlds, the entire wave function continues to exist even after measurement. 09:35: And in the case of pilot wave theory, the wave function contains hidden information that is carried with the final measured particle. 04:51: The time dependent Schrodinger equation describes the time evolution of this thing called the wave function. 04:58: The wave function of a system fully describes all of its properties. 05:02: ... of all of its properties, which you can get by taking the square of the wave function. ... 05:10: ... example, the wave function of a particle encapsulates the probability that it will be found in this ... 05:19: ... perfectly predicts both the past and future evolution of a given wave function in any given environment, or in quantum speak, in any given ... 05:36: ... principle, a given wave function in a given potential could mean the wave function of an electron moving ... 06:10: Remember that the wave function encapsulates the distribution of probabilities for a given property. 06:42: If this is true, and it must be, we say that the time evolution of the wave function is unitary. 08:12: That value seems to be chosen randomly based on the probability distribution encoded in the wave function. 08:29: Quantum information refers to the full information content of the wave function, not just what we measure. 08:35: And in principle, make enough measurements and you can extract all of the information from a wave function. 08:41: ... worth mentioning that the collapse of the wave function in the Copenhagen interpretation of quantum mechanics actually does mess ... 08:50: ... that interpretation, the active measurement actually alters the entire wave function causing it to shrink down to the narrow range of possible values implied ... 09:02: But that measured wave function can't then be tracked backwards to recover the past wave function. 09:22: In the case of many-worlds, the entire wave function continues to exist even after measurement. 09:35: And in the case of pilot wave theory, the wave function contains hidden information that is carried with the final measured particle. 08:50: ... that interpretation, the active measurement actually alters the entire wave function causing it to shrink down to the narrow range of possible values implied by the ... 09:22: In the case of many-worlds, the entire wave function continues to exist even after measurement. 06:10: Remember that the wave function encapsulates the distribution of probabilities for a given property. 09:14: ... for example, Everett's many-worlds or the de Broglie-Bohm pilot wave theory preserve this time ... 09:35: And in the case of pilot wave theory, the wave function contains hidden information that is carried with the final measured particle. 09:14: ... for example, Everett's many-worlds or the de Broglie-Bohm pilot wave theory preserve this time ...
	2018-05-16: Noether's Theorem and The Symmetries of Reality 01:22: Its wavelength increases.
	2018-05-09: How Gaia Changed Astronomy Forever 08:02: Gaia even helps us with the pulsar timing array, a galactic scale gravitational wave observatory which we spoke about recently. 04:49: ... shows the tiny Doppler shift-- the stretching or compression of the wavelength of starlight due to the motion towards or away from ...
	2018-05-02: The Star at the End of Time 05:23: The black-body spectrum of a hot object emits relatively more photons at short energetic wavelengths than a cooler object. 05:31: For most of its life, the spectrum of a red dwarf peaks at infrared wavelengths. 05:23: The black-body spectrum of a hot object emits relatively more photons at short energetic wavelengths than a cooler object. 05:31: For most of its life, the spectrum of a red dwarf peaks at infrared wavelengths.
	2018-04-25: Black Hole Swarms 02:26: ... at between five and 15 solid amasses, although, the recent gravitational wave signals detected by LIGO, suggest they may be even more ... 07:48: Besides being very cool and kind of freaky, this result is especially important for the new field of gravitational wave astronomy. 07:57: Now, we keep seeing these gravitational wave signals from black hole merges, and as I've discussed previously, they're kind of confusing. 08:05: ... know that, if we want to understand the source of these gravitational waves. ... 09:17: Last week, we talked about some of the incredible ways for detecting gravitational waves beyond LIGO. 09:26: Majestic potato asked, whether a supernova can produce gravitational waves detectable from Earth? 09:40: Gravitational waves are produced when the quadrupole moment of a mass distribution changes. 09:52: So if the explosion of a supernova is concentrated, say, more on one side, then LIGO could potentially see the resulting gravitational waves. 10:00: Juxtaposed stars asks whether, theoretically, you could build an engine to extract power from gravitational waves via the sticky bead method? 10:29: A couple of you asked whether the gravitational waves interfere with each other? 10:38: Two gravitational waves crossing paths will add together at any one point in space and time. 10:55: You'd need a material capable of blocking gravitational waves. 11:16: ... rogue wolf notes, that stellar gravitational wave detectors, like pulsar timing arrays, are a bit like using the rustling ... 07:48: Besides being very cool and kind of freaky, this result is especially important for the new field of gravitational wave astronomy. 11:16: ... rogue wolf notes, that stellar gravitational wave detectors, like pulsar timing arrays, are a bit like using the rustling of leaves ... 02:26: ... at between five and 15 solid amasses, although, the recent gravitational wave signals detected by LIGO, suggest they may be even more ... 07:57: Now, we keep seeing these gravitational wave signals from black hole merges, and as I've discussed previously, they're kind of confusing. 02:26: ... at between five and 15 solid amasses, although, the recent gravitational wave signals detected by LIGO, suggest they may be even more ... 08:05: ... know that, if we want to understand the source of these gravitational waves. ... 09:17: Last week, we talked about some of the incredible ways for detecting gravitational waves beyond LIGO. 09:26: Majestic potato asked, whether a supernova can produce gravitational waves detectable from Earth? 09:40: Gravitational waves are produced when the quadrupole moment of a mass distribution changes. 09:52: So if the explosion of a supernova is concentrated, say, more on one side, then LIGO could potentially see the resulting gravitational waves. 10:00: Juxtaposed stars asks whether, theoretically, you could build an engine to extract power from gravitational waves via the sticky bead method? 10:29: A couple of you asked whether the gravitational waves interfere with each other? 10:38: Two gravitational waves crossing paths will add together at any one point in space and time. 10:55: You'd need a material capable of blocking gravitational waves. 10:38: Two gravitational waves crossing paths will add together at any one point in space and time. 09:26: Majestic potato asked, whether a supernova can produce gravitational waves detectable from Earth? 10:29: A couple of you asked whether the gravitational waves interfere with each other?
	2018-04-18: Using Stars to See Gravitational Waves 00:07: Now that gravitational waves are definitely a thing, it's time to think about some of the crazy things we can figure out with them. 00:14: In some cases, we're going to need a gravitational wave observatory the size of a galaxy. 00:23: [MUSIC PLAYING] We are at the cusp of a golden age of gravitational wave astronomy. 00:31: We've already talked about the Laser Interferometer Gravitational-Wave Observatory, LIGO, and the first discovery of gravitational waves here. 02:00: Yet, everyone wants in on the gravitational wave game. 02:09: Perhaps these gravitational waves signals were amplified by another phenomenon predicted by Einstein's general relativity, gravitational lensing. 02:19: ... paths of gravitational waves should also be warped by intervening gravitational fields which can ... 02:45: For the first time, the event behind a gravitational wave signal was also seen in light. 02:59: ... like this should allow us to figure out where the gravitational wave signals are often also gravitationally ... 03:10: ... the Italian-based gravitational wave observatory, was online for the neutron star merger, and was extremely ... 03:49: ... that live in the centers of galaxies, we need to observe gravitational waves in the 0.1 million hertz to 0.1 hertz ... 05:00: ... expect a faint gravitational wave background buzz from an earlier epoch of the universe in which binary ... 05:23: But much of this gravitational wave background will have wavelengths as long as many light years. 05:28: That's beyond any gravitational wave interferometer that we could ever physically construct. 05:51: We're already using these to study the gravitational wave background at the 1 to 100 nanohertz range. 06:17: ... pulsar array volume due to the passage of impossibly vast gravitational waves. ... 06:27: This galaxy scale observatory is already in operation and has placed valuable limits on the amplitude of the gravitational wave background. 06:44: Some scientists are even trying to see how gravitational waves should interact with stars. 06:58: He came up with a thought experiment of a simple gravitational wave detector, a rod with two sliding beads. 07:05: ... a gravitational wave passes by, the beads are free to follow the expansion and contraction of ... 07:18: That heat energy comes from the gravitational wave. 07:21: ... but it demonstrates that in the right circumstances gravitational waves should be able to dump some of their energy into matter, for example, ... 07:38: If a gravitation wave frequency matches the natural resonant frequency of a star, oscillations can be set up inside the star. 07:52: ... binary supermassive black holes that are generating gravitational waves. ... 08:19: Gravitational wave astronomy is currently in a gold rush. 08:40: ... theory of relativity, which predicted the existence of gravitational waves, he had to master it precursor, Newtonian ... 00:23: [MUSIC PLAYING] We are at the cusp of a golden age of gravitational wave astronomy. 08:19: Gravitational wave astronomy is currently in a gold rush. 05:00: ... expect a faint gravitational wave background buzz from an earlier epoch of the universe in which binary supermassive ... 05:23: But much of this gravitational wave background will have wavelengths as long as many light years. 05:51: We're already using these to study the gravitational wave background at the 1 to 100 nanohertz range. 06:27: This galaxy scale observatory is already in operation and has placed valuable limits on the amplitude of the gravitational wave background. 05:00: ... expect a faint gravitational wave background buzz from an earlier epoch of the universe in which binary supermassive black ... 06:58: He came up with a thought experiment of a simple gravitational wave detector, a rod with two sliding beads. 07:38: If a gravitation wave frequency matches the natural resonant frequency of a star, oscillations can be set up inside the star. 02:00: Yet, everyone wants in on the gravitational wave game. 05:28: That's beyond any gravitational wave interferometer that we could ever physically construct. 00:14: In some cases, we're going to need a gravitational wave observatory the size of a galaxy. 03:10: ... the Italian-based gravitational wave observatory, was online for the neutron star merger, and was extremely important in ... 07:05: ... a gravitational wave passes by, the beads are free to follow the expansion and contraction of space ... 02:45: For the first time, the event behind a gravitational wave signal was also seen in light. 02:59: ... like this should allow us to figure out where the gravitational wave signals are often also gravitationally ... 02:19: ... gravitational fields which can amplify the signal and stretch out the wavelengths. ... 05:23: But much of this gravitational wave background will have wavelengths as long as many light years. 02:19: ... gravitational fields which can amplify the signal and stretch out the wavelengths. ... 05:23: But much of this gravitational wave background will have wavelengths as long as many light years. 00:07: Now that gravitational waves are definitely a thing, it's time to think about some of the crazy things we can figure out with them. 00:31: We've already talked about the Laser Interferometer Gravitational-Wave Observatory, LIGO, and the first discovery of gravitational waves here. 02:09: Perhaps these gravitational waves signals were amplified by another phenomenon predicted by Einstein's general relativity, gravitational lensing. 02:19: ... paths of gravitational waves should also be warped by intervening gravitational fields which can ... 03:49: ... that live in the centers of galaxies, we need to observe gravitational waves in the 0.1 million hertz to 0.1 hertz ... 06:17: ... pulsar array volume due to the passage of impossibly vast gravitational waves. ... 06:44: Some scientists are even trying to see how gravitational waves should interact with stars. 07:21: ... but it demonstrates that in the right circumstances gravitational waves should be able to dump some of their energy into matter, for example, ... 07:52: ... binary supermassive black holes that are generating gravitational waves. ... 08:40: ... theory of relativity, which predicted the existence of gravitational waves, he had to master it precursor, Newtonian ... 02:09: Perhaps these gravitational waves signals were amplified by another phenomenon predicted by Einstein's general relativity, gravitational lensing.
	2018-04-11: The Physics of Life (ft. It's Okay to be Smart & PBS Eons!) 09:32: Waves and vortices have their own complex and regular structures, but they ultimately serve to dissipate the flow. 12:59: ... horizon should produce a type of Hawking radiation, but its wavelength would be comparable to the distance to that horizon, so it's completely ... 09:32: Waves and vortices have their own complex and regular structures, but they ultimately serve to dissipate the flow.
	2018-04-04: The Unruh Effect 09:46: ... even in classical systems, like this really cool study with water waves. ...
	2018-03-28: The Andromeda-Milky Way Collision 06:20: When those black holes are around a light year apart, they'll start losing orbital energy to gravitational waves.
	2018-03-21: Scientists Have Detected the First Stars 00:23: Not everything wows, like gravitational waves or space-faring sports cars. 01:42: That photon has a wavelength of 21 centimeters, which is radio light. 03:08: Absorption at 21 centimeters would now look like absorption at a much longer wavelength. 03:14: In fact, there should be this broad dip at a range of wavelengths, representing the epoch of the universe in which this absorption was occurring. 03:55: The wavelength range of the dip corresponds to the epoch between 180 to 270 million years after the Big Bang. 03:14: In fact, there should be this broad dip at a range of wavelengths, representing the epoch of the universe in which this absorption was occurring. 00:23: Not everything wows, like gravitational waves or space-faring sports cars.
	2018-03-15: Hawking Radiation 07:27: And so it produces wave packets. 07:18: Black holes tend to scatter modes with wavelengths similar to their own sizes. 07:23: The quantum field that emerges is distorted in the same wavelength range. 07:29: It produces particles that also have wavelengths about as large as the event horizon. 07:34: So the more massive the black hole, the longer the wavelength of its radiation. 08:51: Remember that Hawking radiation has wavelengths the size of the event horizon, the size of the entire black hole. 08:57: Well, these are the de Broglie wavelengths of created particles. 07:23: The quantum field that emerges is distorted in the same wavelength range. 07:18: Black holes tend to scatter modes with wavelengths similar to their own sizes. 07:29: It produces particles that also have wavelengths about as large as the event horizon. 08:51: Remember that Hawking radiation has wavelengths the size of the event horizon, the size of the entire black hole. 08:57: Well, these are the de Broglie wavelengths of created particles.
	2018-03-07: Should Space be Privatized? 04:28: Asteroid mining seems likely to drive the next wave of private enterprise, because the potential profits are astronomical.
	2018-01-24: The End of the Habitable Zone 08:03: ... the initial extinction wave from the loss of much of Earth's plant life, other complex multicellular ...
	2018-01-17: Horizon Radiation 05:19: As we saw in our recent episode on Fourier transforms, it's possible to describe any vibration or wave in two ways. 05:28: Sound waves can be described in terms of variation over time or variation over frequency. 05:35: Quantum wave functions and quantum fields can be described in terms of variation with position or variations with momentum. 07:51: They behave like simple harmonic oscillators, so their value over time is like a simple sine wave. 05:35: Quantum wave functions and quantum fields can be described in terms of variation with position or variations with momentum. 05:28: Sound waves can be described in terms of variation over time or variation over frequency.
	2018-01-10: What Do Stars Sound Like? 00:14: Believe it or not, we can now map the interiors of stars by listening to their harmonies as they vibrate with seismic waves. 01:13: Well, we may not see light from beneath the stellar surface, but another type of wave travels freely through stars. 01:21: I'm talking about seismic waves. 01:33: ... waves reflect around the stellar interior, setting up global oscillations, ... 02:34: ... earth, seismic waves are generated by earthquakes and can travel around the planet as ... 02:49: And these are true sound waves that echo around their interiors. 02:53: Because stars are fluid rather than solid, they don't support shear waves. 02:57: However, they do support two types of gravity waves. 03:01: Now, these are not gravitational waves. 03:04: Gravity waves result from the restoration of gravitational equilibrium. 03:14: In stars, these waves occur below the surface, g-waves, and on the surface, f-waves. 03:20: The latter are closely analogous to ocean surface waves on the earth. 03:24: However, it's the pressure waves-- the p-waves-- that really dominate in stars like the sun. 03:30: ... acoustic waves are generated by turbulence just below the surface of a star, just as ... 03:41: They start as traveling waves that can move throughout the stars in a structure. 03:45: ... just as a single tap can set an entire bell ringing, a single traveling wave feeds its energy into standing pressure waves that cause the entire star ... 08:12: ... helioseismic holography, the visible wave field-- so the distribution of Doppler velocities across the visible ... 03:45: ... just as a single tap can set an entire bell ringing, a single traveling wave feeds its energy into standing pressure waves that cause the entire star to ... 08:12: ... helioseismic holography, the visible wave field-- so the distribution of Doppler velocities across the visible surface of ... 01:13: Well, we may not see light from beneath the stellar surface, but another type of wave travels freely through stars. 00:14: Believe it or not, we can now map the interiors of stars by listening to their harmonies as they vibrate with seismic waves. 01:21: I'm talking about seismic waves. 01:33: ... waves reflect around the stellar interior, setting up global oscillations, ... 02:34: ... earth, seismic waves are generated by earthquakes and can travel around the planet as ... 02:49: And these are true sound waves that echo around their interiors. 02:53: Because stars are fluid rather than solid, they don't support shear waves. 02:57: However, they do support two types of gravity waves. 03:01: Now, these are not gravitational waves. 03:04: Gravity waves result from the restoration of gravitational equilibrium. 03:14: In stars, these waves occur below the surface, g-waves, and on the surface, f-waves. 03:20: The latter are closely analogous to ocean surface waves on the earth. 03:24: However, it's the pressure waves-- the p-waves-- that really dominate in stars like the sun. 03:30: ... acoustic waves are generated by turbulence just below the surface of a star, just as ... 03:41: They start as traveling waves that can move throughout the stars in a structure. 03:45: ... ringing, a single traveling wave feeds its energy into standing pressure waves that cause the entire star to ... 08:12: ... surface of the sun-- is used to infer the current state of the standing waves throughout the ... 03:14: In stars, these waves occur below the surface, g-waves, and on the surface, f-waves. 01:33: ... waves reflect around the stellar interior, setting up global oscillations, natural ... 03:04: Gravity waves result from the restoration of gravitational equilibrium.
	2017-12-06: Understanding the Uncertainty Principle with Quantum Fourier Series 00:16: ... the humble sound wave is going to open the door to really understanding Heisenberg's ... 02:24: See, quantum mechanics is a type of wave mechanics. 02:29: However, it turns out that something like the uncertainty principle arises in any wave mechanics. 02:35: So let's choose a type of wave that's a little more intuitive, sound waves. 02:41: You can describe a sound wave just as the intensity of the wave as it passes by. 02:51: That shape determines what the wave sounds like to our ears. 02:55: The sound wave for a simple pure tone, like a middle C, is a sinusoidal wave, with the frequency determining the pitch of the tone. 03:03: ... sound wave from, say, an orchestra is extremely complex, but amazingly, it can ... 03:23: ... states that any complex sound wave can be decomposed into a number of sine waves of different frequencies, ... 03:36: ... fact, instead of representing a sound wave in terms of intensity changing with time, you can also represent it in ... 04:02: In the physics of sound, time and frequency have a special relationship because any sound wave can be represented in terms of one or the other. 04:18: So we can make any shape sound wave with a series of sine waves of different frequencies. 04:24: ... example, you can build a wave packet by adding frequency components with the right phases to ... 04:35: The tighter you want to make that time window for the wave packet, the more frequency components you need to use. 04:41: ... fact, to get those steep edges of the wave packet, you need to add higher and higher frequencies, because the high ... 04:52: So what if you try to compress the wave packet to a single spike? 05:01: Is it even possible to make an instantaneous spike at one point in time out of a bunch of sine waves that themselves extend infinitely through time? 05:12: ... point in time, you need to use infinitely many different frequency sine waves, each of which exists at all points in ... 05:30: ... the same time, a sound wave with a perfectly known frequency is a simple traveling sine wave that ... 05:41: That sounds an awful lot like a frequency-time uncertainty principle for sound waves. 05:47: ... it's not really a statement about the fundamental knowability of a sound wave, as is Heisenberg's uncertainty principle, it's more a statement about ... 06:04: Well, before we get back to quantum fields, let's think about the wave function. 06:15: Like the sound wave, it oscillates through space at a particular frequency. 06:20: To keep things simple, we're just going to consider a wave function that doesn't vary in time. 06:27: This is more like a standing sound wave inside an organ pipe rather than the traveling sound wave familiar. 06:43: See, momentum is sort of the generalization of frequency for what we call a matter wave. 06:49: In the early days of quantum mechanics, it was realized that photons are electromagnetic wave packets whose momentum is given by their frequency. 06:58: ... generalizes the relationship between frequency and momentum of a matter wave. ... 07:08: ... now call matter waves wave functions, and we can describe them in terms of position or ... 07:21: So any particle, any wave function, can be represented as a combination of many locations in space, with accompanying intensities. 07:41: And of course, this means that position and momentum have the same kind of uncertainty relation that time and frequency had in the sound wave. 07:50: But what does it even mean for a particle to be comprised of waves of many different positions or momenta? 07:57: To answer this, we need one more bit of physics; the interpretation of the wave function itself, known as the Born rule. 08:06: The magnitude of the wave function squared is the probability distribution for the particle. 08:12: ... we're expressing the wave function in terms of position, then applying the Born rule tells us how ... 08:38: So if we measure a particle's position, then from our point of view, it's wave function is highly localized in space. 08:48: ... resulting particle wave packet, now constrained in position, can only be described as a ... 09:00: The result is a very fat momentum wave function that gives a wide range of possible momenta. 09:06: ... precisely we try to measure position, the narrower we make its position wave function, and so the less certain we become about its momentum, as that ... 09:50: It's an unavoidable outcome of describing particles as the superposition of waves. 09:55: Waves that can be represented in terms of either position or momentum. 09:59: The fact that both can't be known simultaneously with perfect precision is a property of the nature of the wave function itself. 06:27: This is more like a standing sound wave inside an organ pipe rather than the traveling sound wave familiar. 06:04: Well, before we get back to quantum fields, let's think about the wave function. 06:20: To keep things simple, we're just going to consider a wave function that doesn't vary in time. 07:21: So any particle, any wave function, can be represented as a combination of many locations in space, with accompanying intensities. 07:57: To answer this, we need one more bit of physics; the interpretation of the wave function itself, known as the Born rule. 08:06: The magnitude of the wave function squared is the probability distribution for the particle. 08:12: ... we're expressing the wave function in terms of position, then applying the Born rule tells us how likely we ... 08:38: So if we measure a particle's position, then from our point of view, it's wave function is highly localized in space. 09:00: The result is a very fat momentum wave function that gives a wide range of possible momenta. 09:06: ... precisely we try to measure position, the narrower we make its position wave function, and so the less certain we become about its momentum, as that momentum ... 09:59: The fact that both can't be known simultaneously with perfect precision is a property of the nature of the wave function itself. 08:06: The magnitude of the wave function squared is the probability distribution for the particle. 07:08: ... now call matter waves wave functions, and we can describe them in terms of position or momentum, just as a ... 06:27: This is more like a standing sound wave inside an organ pipe rather than the traveling sound wave familiar. 02:24: See, quantum mechanics is a type of wave mechanics. 02:29: However, it turns out that something like the uncertainty principle arises in any wave mechanics. 04:24: ... example, you can build a wave packet by adding frequency components with the right phases to destructively ... 04:35: The tighter you want to make that time window for the wave packet, the more frequency components you need to use. 04:41: ... fact, to get those steep edges of the wave packet, you need to add higher and higher frequencies, because the high ... 04:52: So what if you try to compress the wave packet to a single spike? 05:47: ... a statement about the sampling of frequencies needed to produce a given wave packet. ... 08:48: ... resulting particle wave packet, now constrained in position, can only be described as a superposition of ... 06:49: In the early days of quantum mechanics, it was realized that photons are electromagnetic wave packets whose momentum is given by their frequency. 02:51: That shape determines what the wave sounds like to our ears. 02:35: So let's choose a type of wave that's a little more intuitive, sound waves. 03:03: ... it can always be broken down into a combination of many simple sine waves of different ... 03:23: ... that any complex sound wave can be decomposed into a number of sine waves of different frequencies, each with a different strength, stacked on top ... 04:18: So we can make any shape sound wave with a series of sine waves of different frequencies. 05:01: Is it even possible to make an instantaneous spike at one point in time out of a bunch of sine waves that themselves extend infinitely through time? 05:12: ... point in time, you need to use infinitely many different frequency sine waves, each of which exists at all points in ... 05:41: That sounds an awful lot like a frequency-time uncertainty principle for sound waves. 07:08: ... now call matter waves wave functions, and we can describe them in terms of position or ... 07:50: But what does it even mean for a particle to be comprised of waves of many different positions or momenta? 08:48: ... now constrained in position, can only be described as a superposition of waves with a very large range of different momenta via a Fourier ... 09:50: It's an unavoidable outcome of describing particles as the superposition of waves. 09:55: Waves that can be represented in terms of either position or momentum. 07:08: ... now call matter waves wave functions, and we can describe them in terms of position or momentum, ...
	2017-11-29: Citizen Science + Zero-Point Challenge Answer 03:53: ... example, spotting supernovae or looking for gravitational wave signals in LIGO and finding planets forming in the debris disks of new ... 05:15: But there's also Einstein at Home, which searches for LIGO gravitational wave data for signals produced by rotating neutron stars. 03:53: ... example, spotting supernovae or looking for gravitational wave signals in LIGO and finding planets forming in the debris disks of new solar ... 08:22: That corresponds to a photon wavelength of a tenth of a millimeter, which is in the far infrared part of the spectrum. 08:42: ... with wavelengths shorter than 0.1 millimeters definitely exist, and we see particle ... 09:06: That proves the existence of virtual photons with wavelengths smaller than the plate separation. 08:42: ... we see particle interactions that require the exchange of much shorter wavelength virtual ... 09:06: That proves the existence of virtual photons with wavelengths smaller than the plate separation. 08:42: ... with wavelengths shorter than 0.1 millimeters definitely exist, and we see particle interactions ... 09:06: That proves the existence of virtual photons with wavelengths smaller than the plate separation.
	2017-10-25: The Missing Mass Mystery 04:28: ... like sound waves rippling outwards from high density regions, these baryonic acoustic ... 12:37: TS1336 was expecting last week's episode to be about the discovery of gravitational waves from merging neutron stars. 06:33: This cool gas then absorbs signature wavelengths from light that passes through it. 04:28: ... like sound waves rippling outwards from high density regions, these baryonic acoustic ... 12:37: TS1336 was expecting last week's episode to be about the discovery of gravitational waves from merging neutron stars. 04:28: ... like sound waves rippling outwards from high density regions, these baryonic acoustic oscillations ...
	2017-10-19: The Nature of Nothing 08:51: ... organ pipe or a guitar string of a particular length only resonates with waves of certain frequencies, any non-resonant virtual photon would be ...
	2017-10-11: Absolute Cold 02:53: Once nearly all particles occupy that one quantum state, they share a single, coherent wave function. 08:38: ... binary to spiral together from losing angular momentum to gravitational waves. ... 02:53: Once nearly all particles occupy that one quantum state, they share a single, coherent wave function. 08:38: ... binary to spiral together from losing angular momentum to gravitational waves. ...
	2017-10-04: When Quasars Collide STJC 03:59: ... sides of the planet, and phase differences in the incoming radio waves are used to find the origin of each wave with incredible ... 06:14: Spiraling electrons produce radio waves a lots of frequencies all the way down to very low energies. 06:21: ... we think the matter should be so dense that the lowest energy radio waves have trouble escaping the ... 08:32: A lot of you are probably thinking, what about gravitational waves? 08:45: And can LIGO see those waves? 08:52: ... this system is definitely producing gravitational waves, but it's going to take many billions of years to lose enough angular ... 09:01: And while those waves may be powerful, they have an incredibly low frequency-- something like 1 ten trillionth of a hertz. 09:10: LIGO is sensitive to gravitational waves from 10 to 10,000 hertz. 09:19: ... of a supermassive black hole binary with a galaxy-sized gravitational wave observatory called a pulsar timing ... 06:30: Now, this is a process called synchrotron self-absorbtion, and it causes the base of AGN jets to be much fainter at long wavelengths. 09:48: And this galaxy is so dusty that it's hard to peer into the core at other wavelengths of light. 06:30: Now, this is a process called synchrotron self-absorbtion, and it causes the base of AGN jets to be much fainter at long wavelengths. 09:48: And this galaxy is so dusty that it's hard to peer into the core at other wavelengths of light. 03:59: ... sides of the planet, and phase differences in the incoming radio waves are used to find the origin of each wave with incredible ... 06:14: Spiraling electrons produce radio waves a lots of frequencies all the way down to very low energies. 06:21: ... we think the matter should be so dense that the lowest energy radio waves have trouble escaping the ... 08:32: A lot of you are probably thinking, what about gravitational waves? 08:45: And can LIGO see those waves? 08:52: ... this system is definitely producing gravitational waves, but it's going to take many billions of years to lose enough angular ... 09:01: And while those waves may be powerful, they have an incredibly low frequency-- something like 1 ten trillionth of a hertz. 09:10: LIGO is sensitive to gravitational waves from 10 to 10,000 hertz.
	2017-09-28: Are the Fundamental Constants Changing? 04:48: We see this effect in the sharp spikes or dips in light at specific wavelengths when we observe the spectrum of a gas. 06:09: The result is a very small difference in the wavelengths of the spectral lines produced by those transitions. 06:20: Well, the magnitude of this wavelength split depends very strongly on the fine structure constant. 08:26: ... distant quasars and gas clouds are massively redshifted-- their wavelengths stretched out due to the expansion of the ... 13:58: But that's because the distance between atoms is similar to x-ray wavelengths. 06:20: Well, the magnitude of this wavelength split depends very strongly on the fine structure constant. 04:48: We see this effect in the sharp spikes or dips in light at specific wavelengths when we observe the spectrum of a gas. 06:09: The result is a very small difference in the wavelengths of the spectral lines produced by those transitions. 08:26: ... distant quasars and gas clouds are massively redshifted-- their wavelengths stretched out due to the expansion of the ... 13:58: But that's because the distance between atoms is similar to x-ray wavelengths. 08:26: ... distant quasars and gas clouds are massively redshifted-- their wavelengths stretched out due to the expansion of the ...
	2017-09-20: The Future of Space Telescopes 02:12: The wave nature of light causes it to bend or diffract around the edges of a coronagraph back towards the central optical axis. 11:00: ... tantalizing rumor that the LIGO Observatory had detected gravitational waves from the merger of a pair of neutron ... 11:33: Nicholas Martino asks whether gravitational waves are redshifted by the expansion of the universe. 11:40: They have to travel along the same space-time fabric as light waves, after all. 11:45: I mean, there are waves in that fabric. 11:48: So stretch out the fabric and you stretch out its waves. 02:12: The wave nature of light causes it to bend or diffract around the edges of a coronagraph back towards the central optical axis. 04:50: ... save money as its beneficiary telescope will require no coronagraphs or wavefront correctors or other high-contrast ... 06:16: Light diffracts around the disk, coming to focus on the optical axis where the light's wavefronts line up in constructive interference. 04:50: ... save money as its beneficiary telescope will require no coronagraphs or wavefront correctors or other high-contrast ... 06:16: Light diffracts around the disk, coming to focus on the optical axis where the light's wavefronts line up in constructive interference. 03:27: The number and length of pedals optimizes each starshade for a particular wavelength of light. 08:00: X-rays have such short wavelengths that telescope mirrors have to be astoundingly smooth to reflect them cleanly. 11:00: ... tantalizing rumor that the LIGO Observatory had detected gravitational waves from the merger of a pair of neutron ... 11:33: Nicholas Martino asks whether gravitational waves are redshifted by the expansion of the universe. 11:40: They have to travel along the same space-time fabric as light waves, after all. 11:45: I mean, there are waves in that fabric. 11:48: So stretch out the fabric and you stretch out its waves.
	2017-09-13: Neutron Stars Collide in New LIGO Signal? 00:06: Last year, LIGO announced the detection of gravitational waves from the merger of two black holes. 00:15: ... rumor emerged, that LIGO had for the first time spotted gravitational waves from the collision of a pair of neutron ... 00:37: ... the Laser Interferometer Gravitational Wave Observatory, LIGO, detected gravitational waves from a pair of merging ... 02:55: In fact, the first real evidence of the existence of gravitational waves came from a pulsar. 03:09: This binary pair stirs up spacetime in its vicinity, creating ripples that travel outwards as gravitational waves. 04:46: Smaller mass means weaker gravitational waves. 05:37: ... second before merger, while neutron stars ring at audible gravitational wave frequencies for at least several ... 06:07: "Optical counterpart" means that there's a source of visible light associated with the gravitational wave. 06:12: And in this case, it's from the suspected galaxy that the wave came from. 06:25: ... there's also the rumor that the Italian Gravitational Wave Observatory, VIRGO, also spotted the signal, which helps triangulate the ... 07:32: And the particular observing program that was triggered is one specifically intended for following up on gravitational wave detections. 07:47: Someone in the know decided that this gamma ray burst was very likely associated with a gravitational wave. 09:32: Seeing a gravitational wave signal from merging neutron stars would allow us to determine pretty exactly how much mass is lost in the merger. 09:59: Black hole mergers are dark, so we have to infer almost everything from the gravitational waves alone. 10:11: Comparing the EM and gravitational wave signatures will teach us a lot. 11:42: As it happens, Curiosity Stream has a really excellent overview of LIGO and gravitational waves. 11:49: "Gravitational Waves-- Rewinding Time" includes some fascinating behind-the-scenes footage at the observatories. 07:32: And the particular observing program that was triggered is one specifically intended for following up on gravitational wave detections. 05:37: ... second before merger, while neutron stars ring at audible gravitational wave frequencies for at least several ... 00:37: ... the Laser Interferometer Gravitational Wave Observatory, LIGO, detected gravitational waves from a pair of merging black holes, ... 06:25: ... there's also the rumor that the Italian Gravitational Wave Observatory, VIRGO, also spotted the signal, which helps triangulate the location, ... 00:37: ... the Laser Interferometer Gravitational Wave Observatory, LIGO, detected gravitational waves from a pair of merging black holes, an ... 06:25: ... there's also the rumor that the Italian Gravitational Wave Observatory, VIRGO, also spotted the signal, which helps triangulate the location, but not ... 09:32: Seeing a gravitational wave signal from merging neutron stars would allow us to determine pretty exactly how much mass is lost in the merger. 10:11: Comparing the EM and gravitational wave signatures will teach us a lot. 00:06: Last year, LIGO announced the detection of gravitational waves from the merger of two black holes. 00:15: ... rumor emerged, that LIGO had for the first time spotted gravitational waves from the collision of a pair of neutron ... 00:37: ... Gravitational Wave Observatory, LIGO, detected gravitational waves from a pair of merging black holes, an entirely new realm of the ... 02:55: In fact, the first real evidence of the existence of gravitational waves came from a pulsar. 03:09: This binary pair stirs up spacetime in its vicinity, creating ripples that travel outwards as gravitational waves. 04:46: Smaller mass means weaker gravitational waves. 09:59: Black hole mergers are dark, so we have to infer almost everything from the gravitational waves alone. 11:42: As it happens, Curiosity Stream has a really excellent overview of LIGO and gravitational waves. 11:49: "Gravitational Waves-- Rewinding Time" includes some fascinating behind-the-scenes footage at the observatories.
	2017-08-24: First Detection of Life 01:47: ... dips that result from molecules in Earth's atmosphere absorbing specific wavelengths of light from what would otherwise be the smooth heat glow of the ... 02:24: Going to longer wavelengths we see carbon dioxide, nitrous oxide, methane, ozone, and, well, more water. 01:47: ... dips that result from molecules in Earth's atmosphere absorbing specific wavelengths of light from what would otherwise be the smooth heat glow of the ... 02:24: Going to longer wavelengths we see carbon dioxide, nitrous oxide, methane, ozone, and, well, more water.
	2017-08-10: The One-Electron Universe 08:23: We now think of electrons as oscillations, as waves, in the more fundamental electron field.
	2017-08-02: Dark Flow 01:49: In all directions, it appears to be the same temperature-- around 2.7 Kelvin-- and hence, the same microwave wavelength. 02:13: That motion causes the CMB to be Doppler shifted, its wavelengths a little stretched out behind and a little more compacted ahead.
	2017-07-19: The Real Star Wars 04:56: Then, by passing electromagnetic radiation at a wavelength tuned to an energy level transition in that substance, stimulated emission can occur.
	2017-07-07: Feynman's Infinite Quantum Paths 01:27: ... if each of them travels through both slits, not as a particle but as a wave that fills the intervening space interacts with itself and defines the ... 01:52: ... particles on the screen can be calculated by adding the amplitude of a wave passing through one slit to the amplitude of a wave passing through the ... 02:10: The professor replied, obviously, you have to add together the amplitudes of waves passing through all three slits. 05:58: Schrodinger's wave function and Feynman's path integral describe this probability amplitude thing. 07:01: This is equivalent to the wave function along those paths being perfectly out of phase when they reach the destination. 13:12: ... in the late 19th century as the medium for the propagation of light waves. ... 13:22: It was imagined to be very closely analogous to air as the medium for propagation of sound waves. 05:58: Schrodinger's wave function and Feynman's path integral describe this probability amplitude thing. 07:01: This is equivalent to the wave function along those paths being perfectly out of phase when they reach the destination. 01:52: ... particles on the screen can be calculated by adding the amplitude of a wave passing through one slit to the amplitude of a wave passing through the other ... 02:10: The professor replied, obviously, you have to add together the amplitudes of waves passing through all three slits. 13:12: ... in the late 19th century as the medium for the propagation of light waves. ... 13:22: It was imagined to be very closely analogous to air as the medium for propagation of sound waves. 02:10: The professor replied, obviously, you have to add together the amplitudes of waves passing through all three slits.
	2017-06-28: The First Quantum Field Theory 03:09: For example, in a 3D room full of air, sound waves are oscillations in air density. 03:16: ... is just the average density, but at every point in the room, a sound wave can cause air density to oscillate to higher and lower ... 04:16: Light is a wave in the electromagnetic field. 08:56: All it can do is move particles around via their evolving wave functions. 03:09: For example, in a 3D room full of air, sound waves are oscillations in air density.
	2017-06-21: Anti-Matter and Quantum Relativity 00:50: By the late 1920s, Einstein and Planck had already shown that light is a particle, as well as a wave. 01:21: ... describes how these matter waves, represented as wave functions, change over time, and allowed physicists ... 01:56: ... the Schrodinger equation tracks the evolution of a particle's wave function according to one and only one clock, typically the clock in the ... 02:21: ... with the Schrodinger equation is that it describes particles as simple wave functions, distributions of possible positions and momenta that have no ... 04:16: We now call these two component wave functions, spinors. 01:56: ... the Schrodinger equation tracks the evolution of a particle's wave function according to one and only one clock, typically the clock in the ... 01:21: ... describes how these matter waves, represented as wave functions, change over time, and allowed physicists to predict the evolution of ... 02:21: ... with the Schrodinger equation is that it describes particles as simple wave functions, distributions of possible positions and momenta that have no internal ... 04:16: We now call these two component wave functions, spinors. 01:21: ... describes how these matter waves, represented as wave functions, change over time, and allowed physicists to predict the evolution of quantum ... 02:21: ... with the Schrodinger equation is that it describes particles as simple wave functions, distributions of possible positions and momenta that have no internal ... 04:16: We now call these two component wave functions, spinors. 00:56: And Louis de Broglie had shown that all matter has this dual wave-particle nature. 01:21: ... describes how these matter waves, represented as wave functions, change over time, and allowed physicists ...
	2017-06-07: Supervoids vs Colliding Universes! 01:59: ... billion years of cosmic expansion later, and it stretched to microwave wavelengths, and to a temperature very close to 2.725 Kelvin all across the ... 05:46: ... layman's terms, they split the light from those galaxies into component wavelengths and determined the shift in the wavelengths of those spectra due to the ... 12:48: ... into a spectrum and look for emission lines, light at the signature wavelengths of heavier ... 01:59: ... billion years of cosmic expansion later, and it stretched to microwave wavelengths, and to a temperature very close to 2.725 Kelvin all across the ... 05:46: ... layman's terms, they split the light from those galaxies into component wavelengths and determined the shift in the wavelengths of those spectra due to the ... 12:48: ... into a spectrum and look for emission lines, light at the signature wavelengths of heavier ...
	2017-05-31: The Fate of the First Stars 08:03: ... environment of the old universe, we expect that there were violent waves of star formation followed by cascades of supernova explosions, ripping ... 06:29: Those electrons then lose that energy by emitting light at specific wavelengths-- signature photons that are different for every element or molecule. 10:21: They radiate intense light, with a signature ultraviolet wavelength of hydrogen. 06:29: Those electrons then lose that energy by emitting light at specific wavelengths-- signature photons that are different for every element or molecule. 08:03: ... environment of the old universe, we expect that there were violent waves of star formation followed by cascades of supernova explosions, ripping ...
	2017-04-26: Are You a Boltzmann Brain? 02:54: ... bunched together in one corner or, I don't know, produce a density wave playing "The Ballad of Serenity" over and ...
	2017-04-19: The Oh My God Particle 06:18: When a star explodes, the expanding shock wave carries a strong magnetic field.
	2017-04-05: Telescopes on the Moon 01:51: ... but its biggest advantage is that it can see into near ultraviolet wavelengths and in the visible range observable within our ...
	2017-03-15: Time Crystals! 00:18: [MUSIC PLAYING] In "Space Time Journal Club," we review new scientific papers that are making waves. 04:36: A laser is just a very well-ordered electromagnetic wave with a known period or frequency. 00:18: [MUSIC PLAYING] In "Space Time Journal Club," we review new scientific papers that are making waves.
	2017-03-01: The Treasures of Trappist-1 04:12: Wein's law tells us that the 2,500 Kelvin TRAPPIST-1 star shines brightest at infrared wavelengths.
	2017-02-15: Telescopes of Tomorrow 03:11: But it can also be deflected by the edges of our telescope, like a wave, in a process called diffraction. 05:40: We can think of light from a very distant point-like object-- say a star-- as reaching us as a series of wavefronts. 05:47: Our eyes and our telescopes can focus those wavefronts back into a point. 05:58: But turbulence in the atmosphere warps those wavefronts. 06:43: Its secondary mirrors will be flexible, deformable at high speed by thousands of computer-controlled actuators to correct the warped wavefronts. 05:40: We can think of light from a very distant point-like object-- say a star-- as reaching us as a series of wavefronts. 05:47: Our eyes and our telescopes can focus those wavefronts back into a point. 05:58: But turbulence in the atmosphere warps those wavefronts. 06:43: Its secondary mirrors will be flexible, deformable at high speed by thousands of computer-controlled actuators to correct the warped wavefronts. 01:34: These cameras see mostly at infrared wavelengths of light, unlike Hubble's, which are optimized for visible and ultraviolet light. 01:57: Longer wavelengths of light scatter less easily than shorter wavelengths, and so have an easier time escaping these dust-packed stellar nurseries. 02:06: Compare two shots from Hubble-- this taken in visible wavelengths, this in infrared. 02:11: Webb will see even longer wavelength infrared light and so will bore even deeper. 03:29: The finest detail any telescope can observe is given by the diffraction limit, which increases with wavelength. 03:59: The biggest challenge in observing infrared wavelengths is heat. 04:31: But without sensitivity to visible or ultraviolet wavelengths, it will not replace Hubble. 05:18: Observing in infrared wavelengths is hard. 05:21: But GMT is built to explore visible wavelengths, just like Hubble. 02:11: Webb will see even longer wavelength infrared light and so will bore even deeper. 01:34: These cameras see mostly at infrared wavelengths of light, unlike Hubble's, which are optimized for visible and ultraviolet light. 01:57: Longer wavelengths of light scatter less easily than shorter wavelengths, and so have an easier time escaping these dust-packed stellar nurseries. 02:06: Compare two shots from Hubble-- this taken in visible wavelengths, this in infrared. 03:59: The biggest challenge in observing infrared wavelengths is heat. 04:31: But without sensitivity to visible or ultraviolet wavelengths, it will not replace Hubble. 05:18: Observing in infrared wavelengths is hard. 05:21: But GMT is built to explore visible wavelengths, just like Hubble.
	2017-02-02: The Geometry of Causality 10:50: Janna Levin's "Black Hole Blues" is a wonderful take on the new window that gravitational waves are opening on our universe.
	2017-01-25: Why Quasars are so Awesome 07:54: Waves of star formation, followed by waves of supernovae. 09:45: ... their supermassive black holes merge, the violence will deliver one last wave of fuel to the combined galactic core, and a new quasar will shine ... 03:05: For one thing, its spectrum was redshifted, the wavelength of its light stretched out as those photons traveled through the expanding universe. 07:54: Waves of star formation, followed by waves of supernovae.
	2017-01-11: The EM Drive: Fact or Fantasy? 00:59: Most often, they turn out to be in error, like Opera's faster than light neutrinos and the BICEP2 primordial gravitational waves. 01:44: A resonant radiation field is induced inside, so microwave standing waves reflecting between the ends. 06:49: So the last part of the paper talks about a connection between the EmDrive and pilot wave theory. 07:02: The paper invokes pilot wave theory as a way to justify treating the quantum vacuum as a sort of plasma with which it can exchange momentum. 07:12: However, it's highly speculative and isn't necessarily even an obvious outcome of pilot wave theory. 07:59: Instead, they invoke pilot wave theory to justify treating the quantum vacuum as a deformable medium. 12:28: Speaking of not using radio, Richy Rich and Gareth Dean had a nice discussion on whether aliens would use radio waves. 06:49: So the last part of the paper talks about a connection between the EmDrive and pilot wave theory. 07:02: The paper invokes pilot wave theory as a way to justify treating the quantum vacuum as a sort of plasma with which it can exchange momentum. 07:12: However, it's highly speculative and isn't necessarily even an obvious outcome of pilot wave theory. 07:59: Instead, they invoke pilot wave theory to justify treating the quantum vacuum as a deformable medium. 00:59: Most often, they turn out to be in error, like Opera's faster than light neutrinos and the BICEP2 primordial gravitational waves. 01:44: A resonant radiation field is induced inside, so microwave standing waves reflecting between the ends. 12:28: Speaking of not using radio, Richy Rich and Gareth Dean had a nice discussion on whether aliens would use radio waves. 01:44: A resonant radiation field is induced inside, so microwave standing waves reflecting between the ends.
	2017-01-04: How to See Black Holes + Kugelblitz Challenge Answer 02:33: ... recent observations of gravitational waves from a pair of merging black holes by LIGO could be considered our first ... 04:28: ... and microlensing studies, and of course, more LIGO gravitational waves observations, over the next few years, we'll have mapped the space ... 03:06: They use very long baseline interferometry, VLBI, to synthesize observations at millimeter and submillimeter wavelengths. 04:09: At visible wavelengths, this should look like a brightening of the star, an effect called microlensing. 03:06: They use very long baseline interferometry, VLBI, to synthesize observations at millimeter and submillimeter wavelengths. 04:09: At visible wavelengths, this should look like a brightening of the star, an effect called microlensing. 02:33: ... recent observations of gravitational waves from a pair of merging black holes by LIGO could be considered our first ... 04:28: ... and microlensing studies, and of course, more LIGO gravitational waves observations, over the next few years, we'll have mapped the space ...
	2016-12-21: Have They Seen Us? 07:49: But if such radio waves travel to us from the earliest of times, then they become stretched out as they travel through an expanding universe. 07:40: That emission, produced at 21 centimeters wavelength, or 1420 megahertz frequency, is, by definition, one of the boundaries of the waterhole. 07:49: But if such radio waves travel to us from the earliest of times, then they become stretched out as they travel through an expanding universe.
	2016-12-14: Escape The Kugelblitz Challenge 06:46: Maybe the outgoing light wave will destroy the alien ships.
	2016-12-08: What Happens at the Event Horizon? 14:02: Now, a lot of you wondered why I never mentioned the EM drive when talking about pilot wave theory. 14:14: ... thrust produced by their EM drive and then go on to talk about how pilot wave theory might explain the apparent conservation of momentum-breaking ... 14:30: I might get into the details in an upcoming episode, but for the sake of explaining pilot wave theory this paper isn't relevant. 14:38: ... is extremely speculative, and honestly I wondered whether pilot wave theory was chosen partly because the internet happens to love it at the ... 14:50: ... asks how it can be that pilot wave theory predicts different particle trajectories, given that the ... 15:11: ... pilot wave theory states that the particle riding the wave does have a definite ... 15:22: So if you know the position perfectly and you know the wave function, you can perfectly predict future locations. 15:51: More generally, it allows pilot wave theory to agree with Heisenberg's uncertainty principle. 16:05: ... Broglie-Bohm pilot wave theory states that this uncertainty just arises from our imperfect ... 16:26: That velocity information is in the guiding wave. 16:29: ... extremely interesting papers that detail certain failings of the pilot wave ... 16:38: I'll link those and a couple of others that take different sides in the description of this video, as well as in the pilot wave episode. 16:47: ... really heated and fascinating discussion both for and against the pilot wave interpretation and some of it was from people who know a good deal more ... 17:15: ... entirely accurate when I said that De Broglie, the founder of pilot wave theory, remained convinced by Niels Bohr and his Copenhagen camp, even ... 17:42: ... De Broglie from his 1956 book, he, Bohm, assumes that the [INAUDIBLE] wave is a physical reality, even the [INAUDIBLE] wave in configuration ... 18:01: In fact, De Broglie was never a huge fan even of his own simplistic particle carried by a wave idea. 18:08: ... solution theory in which the so-called particle was actually a matter wave itself embedded in and carried by the sine wave, represented by the wave ... 18:57: ... De Broglie-Bohm pilot wave theory is a great example of how a deterministic theory can at least go ... 19:07: Personally, I'm agnostic towards the relative truth behind the Copenhagen, many-worlds, pilot wave, or the other interpretations of quantum mechanics. 16:38: I'll link those and a couple of others that take different sides in the description of this video, as well as in the pilot wave episode. 15:22: So if you know the position perfectly and you know the wave function, you can perfectly predict future locations. 18:08: ... wave itself embedded in and carried by the sine wave, represented by the wave function. ... 18:01: In fact, De Broglie was never a huge fan even of his own simplistic particle carried by a wave idea. 16:29: ... extremely interesting papers that detail certain failings of the pilot wave interpretation. ... 16:47: ... really heated and fascinating discussion both for and against the pilot wave interpretation and some of it was from people who know a good deal more than I do, like ... 18:08: ... was actually a matter wave itself embedded in and carried by the sine wave, represented by the wave ... 14:02: Now, a lot of you wondered why I never mentioned the EM drive when talking about pilot wave theory. 14:14: ... thrust produced by their EM drive and then go on to talk about how pilot wave theory might explain the apparent conservation of momentum-breaking ... 14:30: I might get into the details in an upcoming episode, but for the sake of explaining pilot wave theory this paper isn't relevant. 14:38: ... is extremely speculative, and honestly I wondered whether pilot wave theory was chosen partly because the internet happens to love it at the ... 14:50: ... asks how it can be that pilot wave theory predicts different particle trajectories, given that the particles ... 15:11: ... pilot wave theory states that the particle riding the wave does have a definite position ... 15:51: More generally, it allows pilot wave theory to agree with Heisenberg's uncertainty principle. 16:05: ... Broglie-Bohm pilot wave theory states that this uncertainty just arises from our imperfect knowledge ... 17:15: ... entirely accurate when I said that De Broglie, the founder of pilot wave theory, remained convinced by Niels Bohr and his Copenhagen camp, even after ... 18:57: ... De Broglie-Bohm pilot wave theory is a great example of how a deterministic theory can at least go some ... 14:50: ... asks how it can be that pilot wave theory predicts different particle trajectories, given that the particles supposedly all ... 17:15: ... entirely accurate when I said that De Broglie, the founder of pilot wave theory, remained convinced by Niels Bohr and his Copenhagen camp, even after Bohm's ... 15:11: ... pilot wave theory states that the particle riding the wave does have a definite position at all ... 16:05: ... Broglie-Bohm pilot wave theory states that this uncertainty just arises from our imperfect knowledge and that ...
	2016-11-30: Pilot Wave Theory and Quantum Realism 00:55: ... explanations claim stuff like things are both waves and particles at the same time, the act of observation defines reality, ... 02:27: One aspect of that radical thinking was that the wave function is not a wave in anything physical but an abstract distribution of probabilities. 02:36: ... the properties of, say, the particle that would emerge from its wave ... 02:59: This required an almost mystical duality between the wave and particle-like nature of matter. 03:11: ... to be a full theory that described how a quantum object could show both wave and particle-like behavior at the same time without being fundamentally ... 03:25: ... guy who originally proposed the idea that matter could be described as waves right at the beginning of the quantum ... 03:36: De Broglie's theory reasoned that there was no need for quantum objects to transition in a mystical way between non-real waves and real particles. 03:46: Why not just have real waves that push around real particles? 03:54: In it, the wave function describes a real wave of some stuff. 03:59: This wave guides the motion of a real point-like particle that has a definite location at all times. 04:05: Importantly, the wave function in pilot-wave theory evolves exactly according to the Schrodinger equation. 04:13: That's the equation at the heart of all quantum mechanics that tells the wave function how to change across space and time. 04:28: For example, this guiding wave does all the usual wavy stuff, like form an interference pattern when it passes through a pair of slits. 04:37: Because particles follow the paths etched out by the wave, it'll end up landing according to that pattern. 04:45: The wave defines a set of possible trajectories and the particle takes one of those trajectories. 07:05: ... well as the Schrodinger equation that tells the wave function how to change, it also has a guiding equation that tells the ... 07:24: However, the guiding equation is derived directly from the wave function, so some would argue that it was there all along. 07:32: A more troubling requirement of Bohmian mechanics is that it does contain real complexity that is not encoded in the wave function. 07:44: Bohmian mechanics has so-called hidden variables, details about the state of the particle that are not described by the wave function. 07:51: According to pilot-wave theory, the wave function just describes the possible distribution of those variables given our lack of perfect knowledge. 08:05: ... published a proof showing that hidden variable explanations for the wave function just couldn't ... 08:34: So there can't be extra information about a specific region of the wave function that the rest of the wave function doesn't know. 09:07: The entire wave function knows the location, velocity, and spin of each particle. 09:18: Not only does the entire wave function know the properties of the particle, but the entire wave function can be effected instantaneously. 09:25: So a measurement at one point in the wave function will affect its shape elsewhere. 09:30: This can therefore affect the trajectories and properties of particles carried by that wave, potentially very far away. 04:45: The wave defines a set of possible trajectories and the particle takes one of those trajectories. 02:27: One aspect of that radical thinking was that the wave function is not a wave in anything physical but an abstract distribution of probabilities. 02:36: ... the properties of, say, the particle that would emerge from its wave function. ... 03:54: In it, the wave function describes a real wave of some stuff. 04:05: Importantly, the wave function in pilot-wave theory evolves exactly according to the Schrodinger equation. 04:13: That's the equation at the heart of all quantum mechanics that tells the wave function how to change across space and time. 07:05: ... well as the Schrodinger equation that tells the wave function how to change, it also has a guiding equation that tells the particle ... 07:24: However, the guiding equation is derived directly from the wave function, so some would argue that it was there all along. 07:32: A more troubling requirement of Bohmian mechanics is that it does contain real complexity that is not encoded in the wave function. 07:44: Bohmian mechanics has so-called hidden variables, details about the state of the particle that are not described by the wave function. 07:51: According to pilot-wave theory, the wave function just describes the possible distribution of those variables given our lack of perfect knowledge. 08:05: ... published a proof showing that hidden variable explanations for the wave function just couldn't ... 08:34: So there can't be extra information about a specific region of the wave function that the rest of the wave function doesn't know. 09:07: The entire wave function knows the location, velocity, and spin of each particle. 09:18: Not only does the entire wave function know the properties of the particle, but the entire wave function can be effected instantaneously. 09:25: So a measurement at one point in the wave function will affect its shape elsewhere. 03:54: In it, the wave function describes a real wave of some stuff. 08:34: So there can't be extra information about a specific region of the wave function that the rest of the wave function doesn't know. 03:59: This wave guides the motion of a real point-like particle that has a definite location at all times. 04:37: Because particles follow the paths etched out by the wave, it'll end up landing according to that pattern. 00:55: ... explanations claim stuff like things are both waves and particles at the same time, the act of observation defines reality, ... 03:25: ... guy who originally proposed the idea that matter could be described as waves right at the beginning of the quantum ... 03:36: De Broglie's theory reasoned that there was no need for quantum objects to transition in a mystical way between non-real waves and real particles. 03:46: Why not just have real waves that push around real particles?
	2016-11-16: Strange Stars 12:50: A lot of you asked for a video on De Brogile-Bohm pilot wave theory.
	2016-11-09: Did Dark Energy Just Disappear? 14:40: ... interference bands when the distance between the slits is similar to the wavelength of the light, and with slit widths significantly narrower than that ...
	2016-10-26: The Many Worlds of the Quantum Multiverse 00:53: Mathematically, this is encapsulated in the wave function of a quantum particle or system of particles. 01:17: These particles arrive at the screen distributed like the interference pattern you would expect from a simple wave. 02:16: It collapses the wave function. 03:17: But why can't the cat collapse its own wave function? 03:55: ... the wave functions describing quantum systems overlap sufficiently-- in other ... 05:12: What if the wave function never collapses? 06:00: ... Everett in his 1957 PhD thesis entitled "The Theory of the Universal Wave Function." It's come to be known as the many worlds ... 07:31: It seems extravagant to propose uncountable eternally-branching universes just to get out of collapsing a wave function. 07:57: It's just that Copenhagen merges them into a single timeline with its wave function collapsed. 08:04: ... worlds can be thought of as overlayed histories, slices of a universal wave function that diverge from each other as the universe evolves, but none ... 08:18: ... because there's nothing in that math that requires the collapse of the wave ... 10:02: ... happening when these neighboring coherent histories interact or why the wave function translates to probabilities the way it ... 00:53: Mathematically, this is encapsulated in the wave function of a quantum particle or system of particles. 02:16: It collapses the wave function. 03:17: But why can't the cat collapse its own wave function? 05:12: What if the wave function never collapses? 06:00: ... Everett in his 1957 PhD thesis entitled "The Theory of the Universal Wave Function." It's come to be known as the many worlds ... 07:31: It seems extravagant to propose uncountable eternally-branching universes just to get out of collapsing a wave function. 07:57: It's just that Copenhagen merges them into a single timeline with its wave function collapsed. 08:04: ... worlds can be thought of as overlayed histories, slices of a universal wave function that diverge from each other as the universe evolves, but none ever ... 08:18: ... because there's nothing in that math that requires the collapse of the wave function. ... 10:02: ... happening when these neighboring coherent histories interact or why the wave function translates to probabilities the way it ... 07:57: It's just that Copenhagen merges them into a single timeline with its wave function collapsed. 10:02: ... happening when these neighboring coherent histories interact or why the wave function translates to probabilities the way it ... 03:55: ... the wave functions describing quantum systems overlap sufficiently-- in other words, they ...
	2016-10-12: Black Holes from the Dawn of Time 00:25: LIGO's recent observation of gravitational waves from merging black holes is a stunning confirmation of this fact.
	2016-09-21: Quantum Entanglement and the Great Bohr-Einstein Debate 02:00: In between observations, the wave function describing this superposition is a complete description of reality. 02:29: He insisted that the wave function, and by extension quantum mechanics, is incomplete. 03:36: ... requires that we describe the particle pair with a single combined wave function that encompasses all possible states of both ... 03:49: ... measurement of one particle automatically collapses the entire entangled wave function, and so affects the results of measurements of the other ... 05:00: Their wave functions are therefore entangled. 06:35: What if between creation and measurement, the electron and positron only exist as a wave function of all possible states. 06:43: In that case, measurement of one particle spin should cause the entire wave function to collapse, to take on defined values. 08:41: ... confirmed that the Bell inequalities are violated, suggesting that the wave function cannot have local hidden ... 10:53: Also, the De Broglie-Bohm Pilot Wave Theory works by assuming real and non-local hidden variables. 02:00: In between observations, the wave function describing this superposition is a complete description of reality. 02:29: He insisted that the wave function, and by extension quantum mechanics, is incomplete. 03:36: ... requires that we describe the particle pair with a single combined wave function that encompasses all possible states of both ... 03:49: ... measurement of one particle automatically collapses the entire entangled wave function, and so affects the results of measurements of the other ... 06:35: What if between creation and measurement, the electron and positron only exist as a wave function of all possible states. 06:43: In that case, measurement of one particle spin should cause the entire wave function to collapse, to take on defined values. 08:41: ... confirmed that the Bell inequalities are violated, suggesting that the wave function cannot have local hidden ... 02:00: In between observations, the wave function describing this superposition is a complete description of reality. 05:00: Their wave functions are therefore entangled. 10:53: Also, the De Broglie-Bohm Pilot Wave Theory works by assuming real and non-local hidden variables.
	2016-09-07: Is There a Fifth Fundamental Force? + Quantum Eraser Answer 07:19: If either detectors A or B are triggered, then there's an asymmetry in the global wave function, passing through one slit versus the other. 07:32: Admittedly, this decoherence appears to affect the wave function at times before the apparent cause of the decoherence. 07:50: ... without inventing mystical interpretations that somehow give us psychic wave function collapsing powers, as much as we'd all like to believe we have ... 07:19: If either detectors A or B are triggered, then there's an asymmetry in the global wave function, passing through one slit versus the other. 07:32: Admittedly, this decoherence appears to affect the wave function at times before the apparent cause of the decoherence. 07:50: ... without inventing mystical interpretations that somehow give us psychic wave function collapsing powers, as much as we'd all like to believe we have ... 07:19: If either detectors A or B are triggered, then there's an asymmetry in the global wave function, passing through one slit versus the other.
	2016-08-24: Should We Build a Dyson Sphere? 14:04: It's like adding a sign in a cosine wave. 00:53: ... only as strange points of infrared lights but otherwise black at visible wavelengths. ...
	2016-08-10: How the Quantum Eraser Rewrites the Past 01:08: The Copenhagen interpretation would tell us that in this space, a particle is only its wave function, a distribution of possible properties. 01:19: It's a probability wave that does all the usual wave-like stuff like making interference patterns, until something happens to collapse it. 01:29: At that point, the Copenhagen interpretation tells us that a true transition happens between wave and particle. 01:52: ... to believe that observation by a physicist is better at collapsing wave functions then observation by an electronic ... 02:12: But it's still pretty interesting to see what happens if we try to observe the wave function at different points in the double slit experiment. 02:19: The great mystery of the experiment is that very particle-like things appear to traverse both slits simultaneously, like you might expect of a wave. 03:01: ... even true if you place detectors on the far side of the slits after the wave particle thing should have already been interfering with itself, just ... 03:26: It's impossible to make these measurements without messing up the wave. 03:31: ... interference pattern happens because the waves emerging from each slit are what we call coherent, which is a fancy way ... 03:41: So the locations of peaks and valleys is predictable and stays consistent as the waves move forward. 03:49: This coherence is what allows the waves to produce the interference pattern in the first place. 03:54: But when you place some device in the path of either wave, you mess with this coherence, and so affect the pattern that reaches the screen. 05:33: As though any knowledge of which way the original photon traveled stops it from acting like a wave during its passage through the slits. 05:49: So a photon lands on the screen according to the pattern defined by its wave function. 07:29: ... interpretation that observation of the path causes the collapse of the wave function, and that the wave function can collapse all the way back to ... 08:01: ... when a spread out wave function resolves itself into a set of known properties, say, the ... 08:18: But if these wave functions are physical, as the Copenhagen Interpretation would tell us, then there is no real instantaneous physical interaction. 08:27: ... contrast, a physical interpretation of the wave function, like the De Broglie-Bohm Pilot Wave Theory, requires an ... 08:57: Now the delayed choice quantum eraser double slit experiment doesn't tell us whether the wave function is physical or not. 09:04: ... us that the Copenhagen, or any other metaphysical interpretation of the wave function, is no less well, crazy-sounding than a physical ... 03:31: ... which is a fancy way of saying that the relationship between the wave form is emerging from the two ... 01:08: The Copenhagen interpretation would tell us that in this space, a particle is only its wave function, a distribution of possible properties. 02:12: But it's still pretty interesting to see what happens if we try to observe the wave function at different points in the double slit experiment. 03:01: ... thing should have already been interfering with itself, just like the wave function is collapsing retroactively, as if the universe is saying, OK, ... 05:49: So a photon lands on the screen according to the pattern defined by its wave function. 07:29: ... interpretation that observation of the path causes the collapse of the wave function, and that the wave function can collapse all the way back to wherever our ... 08:01: ... when a spread out wave function resolves itself into a set of known properties, say, the location of a ... 08:27: ... contrast, a physical interpretation of the wave function, like the De Broglie-Bohm Pilot Wave Theory, requires an underlying ... 08:57: Now the delayed choice quantum eraser double slit experiment doesn't tell us whether the wave function is physical or not. 09:04: ... us that the Copenhagen, or any other metaphysical interpretation of the wave function, is no less well, crazy-sounding than a physical ... 08:01: ... when a spread out wave function resolves itself into a set of known properties, say, the location of a particle ... 01:52: ... to believe that observation by a physicist is better at collapsing wave functions then observation by an electronic ... 08:18: But if these wave functions are physical, as the Copenhagen Interpretation would tell us, then there is no real instantaneous physical interaction. 03:01: ... even true if you place detectors on the far side of the slits after the wave particle thing should have already been interfering with itself, just like the ... 08:27: ... interpretation of the wave function, like the De Broglie-Bohm Pilot Wave Theory, requires an underlying physicality, a set of defined properties that ... 01:19: It's a probability wave that does all the usual wave-like stuff like making interference patterns, until something happens to collapse it. 03:31: ... interference pattern happens because the waves emerging from each slit are what we call coherent, which is a fancy way ... 03:41: So the locations of peaks and valleys is predictable and stays consistent as the waves move forward. 03:49: This coherence is what allows the waves to produce the interference pattern in the first place. 03:31: ... interference pattern happens because the waves emerging from each slit are what we call coherent, which is a fancy way of saying ...
	2016-08-03: Can We Survive the Destruction of the Earth? ft. Neal Stephenson 11:15: ... suggests that the wave function is nothing more than a distribution of probabilities, and that ... 11:35: ... deterministic interpretation requires that the wave function conceal what we call hidden variables, that may change over ... 11:50: ... ideas is that they require instantaneous communication across the wave function, or between entangled particle pairs, in order to satisfy ... 12:14: vhsjpdfg inquires after the wave functions and interference patterns for massive objects. 12:21: Well, wave functions for macroscopic objects are incredibly complicated because they're comprised of countless quantum particles. 12:30: You can define a theoretical wavelength of a macroscopic object's wave function-- it's the de Broglie wavelength, and it's very, very small. 11:15: ... suggests that the wave function is nothing more than a distribution of probabilities, and that when the ... 11:35: ... deterministic interpretation requires that the wave function conceal what we call hidden variables, that may change over time and ... 11:50: ... ideas is that they require instantaneous communication across the wave function, or between entangled particle pairs, in order to satisfy experimental ... 12:30: You can define a theoretical wavelength of a macroscopic object's wave function-- it's the de Broglie wavelength, and it's very, very small. 11:15: ... is nothing more than a distribution of probabilities, and that when the wave function collapses, the properties of the resulting particle are picked randomly from that ... 11:35: ... deterministic interpretation requires that the wave function conceal what we call hidden variables, that may change over time and space ... 12:14: vhsjpdfg inquires after the wave functions and interference patterns for massive objects. 12:21: Well, wave functions for macroscopic objects are incredibly complicated because they're comprised of countless quantum particles. 12:30: You can define a theoretical wavelength of a macroscopic object's wave function-- it's the de Broglie wavelength, and it's very, very small. 12:39: ... do so you'd need slits whose separation is similar to their de Broglie wavelength. ...
	2016-07-27: The Quantum Experiment that Broke Reality 00:45: Some distance away, those waves encounter a barrier with two gaps cut in it. 00:51: Most of the wave is blocked but ripples pass through the gaps. 01:16: ... call this "constructive interference." But when the peak from one wave encounters the trough from another, they cancel out, leaving nothing, ... 01:34: Any type of wave should make an interference pattern like this, for example, water waves and sound waves but also light waves. 02:01: Of course, we now know that light is a wave in the electromagnetic field thanks to the work of James Clerk Maxwell a century later. 02:33: So each photon is a little bundle of waves, waves of electromagnetic field, and each bundle can't be broken into smaller parts. 03:56: This pattern has nothing to do with how each photon's energy gets spread out, as was the case with the water wave. 04:31: It knows the interference pattern of a pure wave that passed through both slits equally and it chooses its landing point based on that. 05:14: We have to conclude that each individual photon, electron, or buckyball travels through both slits as some sort of wave. 05:23: ... wave then interacts with itself to produce an interference pattern, except ... 05:37: It looks like a wave of possible undefined positions that at some point, for some reason, resolves itself into a single certain position. 06:00: ... mathematical description of this wave-like distribution of properties a "wave function." Describing the behavior of the wave function is the heart of ... 06:12: But what does the wave function represent? 06:14: What are these waves of or waves in? 06:44: ... wave holds the information about all the possible final positions of the ... 06:55: In fact, the wave must map out all possible paths that the particle could take. 07:02: ... could-be trajectories from start to finish and for some reason, when the wave reaches the screen, it chooses a final location and that implies ... 07:18: So what causes this transition between a wave of many possibilities and a well-defined thing at a particular spot? 07:39: We still couldn't figure out what the wave is made of. 07:59: The Copenhagen interpretation says that the wave function doesn't have a physical nature. 08:09: ... that a particle traversing the double-slit experiment exists only as a wave of possible locations that ultimately encompasses all possible ... 08:27: ... a possibility space to a defined set of properties "the collapse of the wave function." It tells us that prior to the collapse, it's meaningless to ... 09:25: ... the universe is fundamentally random within the constraints of the final wave ... 09:49: There are interpretations that give the wave function a physical reality. 09:54: ... we know that light is a wave in the electromagnetic field and quantum field theory tells us that all ... 10:06: This may give us a more physical medium that drives these waves of possibility. 01:16: ... call this "constructive interference." But when the peak from one wave encounters the trough from another, they cancel out, leaving nothing, "destructive ... 06:00: ... mathematical description of this wave-like distribution of properties a "wave function." Describing the behavior of the wave function is the heart of quantum ... 06:12: But what does the wave function represent? 07:59: The Copenhagen interpretation says that the wave function doesn't have a physical nature. 08:27: ... a possibility space to a defined set of properties "the collapse of the wave function." It tells us that prior to the collapse, it's meaningless to try to ... 09:25: ... the universe is fundamentally random within the constraints of the final wave function. ... 09:49: There are interpretations that give the wave function a physical reality. 06:00: ... mathematical description of this wave-like distribution of properties a "wave function." Describing the behavior of the wave function is the heart of quantum ... 07:59: The Copenhagen interpretation says that the wave function doesn't have a physical nature. 06:12: But what does the wave function represent? 06:44: ... wave holds the information about all the possible final positions of the particle ... 07:02: ... could-be trajectories from start to finish and for some reason, when the wave reaches the screen, it chooses a final location and that implies choosing from ... 06:00: ... call the mathematical description of this wave-like distribution of properties a "wave function." Describing the behavior of ... 06:36: So the particle seems to be more particle-like at either end but wave-like in between. 06:00: ... call the mathematical description of this wave-like distribution of properties a "wave function." Describing the behavior of ... 06:36: So the particle seems to be more particle-like at either end but wave-like in between. 06:00: ... call the mathematical description of this wave-like distribution of properties a "wave function." Describing the behavior of the wave ... 00:45: Some distance away, those waves encounter a barrier with two gaps cut in it. 01:34: Any type of wave should make an interference pattern like this, for example, water waves and sound waves but also light waves. 02:33: So each photon is a little bundle of waves, waves of electromagnetic field, and each bundle can't be broken into smaller parts. 06:14: What are these waves of or waves in? 09:54: ... and quantum field theory tells us that all fundamental particles are waves in their own ... 10:06: This may give us a more physical medium that drives these waves of possibility. 00:45: Some distance away, those waves encounter a barrier with two gaps cut in it. 02:33: So each photon is a little bundle of waves, waves of electromagnetic field, and each bundle can't be broken into smaller parts.
	2016-07-20: The Future of Gravitational Waves 00:00: On June 15, the LIGO team announced their second detection of a gravitational wave. 00:14: ... September 14, 2015, the Laser Interferometer Gravitational Wave Observatory, LIGO, detected the gravitational waves from the merger of ... 00:31: ... in the path lengths of the LIGO interferometer arms as the gravitational wave stretched and compressed the fabric of space as it passed ... 00:54: This incredibly important observation was hailed at the time as representing the dawn of gravitational wave astronomy. 01:02: However, that's only true if we ever detect another gravitational wave. 03:20: ... about the December signal when they announced the first gravitational wave detection back in ... 03:38: ... actual fact, LIGO probably saw a third gravitational wave back in October but it wasn't quite strong enough to satisfy the team's ... 04:07: Beyond the detection of gravitational waves, this is another awesome validation of the theory. 05:10: ... LIGO isn't particularly good at figuring out the direction that the wave came from, which is determined by the time difference in the signal ... 05:25: When European Virgo comes online later this year, we expect a massive improvement in our ability to locate the source of the waves. 05:33: Then we can turn all of our telescopes to that spot as soon as a wave is detected. 00:54: This incredibly important observation was hailed at the time as representing the dawn of gravitational wave astronomy. 03:20: ... about the December signal when they announced the first gravitational wave detection back in ... 00:14: ... September 14, 2015, the Laser Interferometer Gravitational Wave Observatory, LIGO, detected the gravitational waves from the merger of two black ... 00:31: ... in the path lengths of the LIGO interferometer arms as the gravitational wave stretched and compressed the fabric of space as it passed ... 01:30: ... waveform looked just like what the researchers were expecting from theoretical ... 00:14: ... Gravitational Wave Observatory, LIGO, detected the gravitational waves from the merger of two black ... 04:07: Beyond the detection of gravitational waves, this is another awesome validation of the theory. 05:25: When European Virgo comes online later this year, we expect a massive improvement in our ability to locate the source of the waves.
	2016-06-29: Nuclear Physics Challenge 00:24: These matter waves don't have perfectly-defined positions, but rather, occupy a range of possible positions. 00:19: But here's TL;DR. Particles of matter have wave-like properties. 00:24: These matter waves don't have perfectly-defined positions, but rather, occupy a range of possible positions.
	2016-06-22: Planck's Constant and The Origin of Quantum Mechanics 09:52: ... clue Einstein needed to hypothesize the existence of the photon-- part wave, part particle, carrying a quantum of energy equal to the now familiar ... 14:34: That's exactly the same type of swirliness that primordial gravitational waves should produce. 14:45: Ed Eggermont wonders if gravitational waves are also subject to gravitational lensing. 14:52: Gravitational waves are ripples in the fabric of space time, so they have to go where the space time goes. 09:52: ... carrying a quantum of energy equal to the now familiar frequency of the wave times the Planck ... 01:31: We talked about this recently when we discussed the de Broglie wavelength. 02:12: ... Heisenberg uncertainty principle and the de Broglie wavelength, but also the Schrodinger equation, the energy levels of electron orbits, ... 14:34: That's exactly the same type of swirliness that primordial gravitational waves should produce. 14:45: Ed Eggermont wonders if gravitational waves are also subject to gravitational lensing. 14:52: Gravitational waves are ripples in the fabric of space time, so they have to go where the space time goes.
	2016-06-15: The Strange Universe of Gravitational Lensing 10:05: ... tunnel, you need to spontaneously find yourself at a point in your wave function that has an equal or lower energy state than your starting ... 10:24: An exponentially decaying part of its wave function is actually inside that wall. 10:29: The particle could find itself located anywhere that its wave function is non-zero. 11:07: So some of the language I used to describe the collapse of the wave function and possible positions did echo the Copenhagen interpretation. 11:37: Prior to that, it exists only as its wave function, which is a distribution of probabilities of these properties. 11:45: ... works, but it's also not deterministic in that in order for the wave function to become a set of physical properties, there needs to be a ... 12:02: ... de Broglie-Bohm pilot wave theory, the many-worlds interpretation, and others, allow a ... 12:16: The wave function that we calculate defines the probability that we will observe a particular set of physical properties. 12:39: ... a quantum system means doing something to it that collapses its wave function into the classical physical properties like position and ... 12:58: ... is another way of saying that a particle's wave function gets so hopelessly mixed with those of other particles that its ... 13:09: However, one view that's not really favored is the idea that a conscious observer is needed to collapse a wave function. 10:05: ... tunnel, you need to spontaneously find yourself at a point in your wave function that has an equal or lower energy state than your starting ... 10:24: An exponentially decaying part of its wave function is actually inside that wall. 10:29: The particle could find itself located anywhere that its wave function is non-zero. 11:07: So some of the language I used to describe the collapse of the wave function and possible positions did echo the Copenhagen interpretation. 11:37: Prior to that, it exists only as its wave function, which is a distribution of probabilities of these properties. 11:45: ... works, but it's also not deterministic in that in order for the wave function to become a set of physical properties, there needs to be a completely ... 12:02: ... allow a deterministic interpretation of the so-called collapse of the wave function. ... 12:16: The wave function that we calculate defines the probability that we will observe a particular set of physical properties. 12:39: ... a quantum system means doing something to it that collapses its wave function into the classical physical properties like position and ... 12:58: ... is another way of saying that a particle's wave function gets so hopelessly mixed with those of other particles that its ... 13:09: However, one view that's not really favored is the idea that a conscious observer is needed to collapse a wave function. 12:02: ... de Broglie-Bohm pilot wave theory, the many-worlds interpretation, and others, allow a deterministic ... 10:54: ... Mayo asks whether my interpretation of the de Broglie wavelength as a range of possible locations is only true for the Copenhagen ...
	2016-06-01: Is Quantum Tunneling Faster than Light? 00:57: That distribution, and the way it changes over time, is coded in the object's wave function. 01:04: The reduction of a fuzzy possibility space into a specific measurable property is sometimes referred to as the collapse of the wave function. 01:30: French mathematician and physicist Louis de Broglie figured out that any material object is really a matter wave. 01:39: It can be described as a wave packet of positioned probability. 01:43: And that wave packet has a wavelength. 02:16: Observe me and you'll collapse my wave function and probably find me pretty much exactly where you expect to. 03:39: As an alpha particle approaches the force barrier of the nucleus, its wave packet is reflected backwards, usually. 03:48: See, that wave packet describes a range of possible locations for the approaching particle. 05:38: Remember the LEGO interferometer that discovered gravitational waves? 05:46: The photon wave packets interact with each other and produce an interference pattern that is incredibly sensitive to differences in path lengths. 06:18: ... like with the alpha particle, as the photon approaches the barrier the wave packet defining its possible location extends weakly beyond the ... 06:51: That will be apparent when their wave packets don't line up perfectly at the other end. 08:39: ... could arrive at the earlier time of the tunneling photon, because its wave packet includes that in its range of possible ... 08:49: When you add the barrier, all you're really doing is reshaping the wave packet, selecting only the possibility space of early arrival. 00:57: That distribution, and the way it changes over time, is coded in the object's wave function. 01:04: The reduction of a fuzzy possibility space into a specific measurable property is sometimes referred to as the collapse of the wave function. 02:16: Observe me and you'll collapse my wave function and probably find me pretty much exactly where you expect to. 01:39: It can be described as a wave packet of positioned probability. 01:43: And that wave packet has a wavelength. 03:39: As an alpha particle approaches the force barrier of the nucleus, its wave packet is reflected backwards, usually. 03:48: See, that wave packet describes a range of possible locations for the approaching particle. 06:18: ... like with the alpha particle, as the photon approaches the barrier the wave packet defining its possible location extends weakly beyond the ... 08:39: ... could arrive at the earlier time of the tunneling photon, because its wave packet includes that in its range of possible ... 08:49: When you add the barrier, all you're really doing is reshaping the wave packet, selecting only the possibility space of early arrival. 06:18: ... like with the alpha particle, as the photon approaches the barrier the wave packet defining its possible location extends weakly beyond the ... 03:48: See, that wave packet describes a range of possible locations for the approaching particle. 08:39: ... could arrive at the earlier time of the tunneling photon, because its wave packet includes that in its range of possible ... 08:49: When you add the barrier, all you're really doing is reshaping the wave packet, selecting only the possibility space of early arrival. 05:46: The photon wave packets interact with each other and produce an interference pattern that is incredibly sensitive to differences in path lengths. 06:51: That will be apparent when their wave packets don't line up perfectly at the other end. 05:46: The photon wave packets interact with each other and produce an interference pattern that is incredibly sensitive to differences in path lengths. 01:43: And that wave packet has a wavelength. 01:46: This de Broglie Wavelength defines how well determined an object's position is. 01:52: A large wavelength means a highly uncertain position. 01:57: A small wavelength means a well-defined position. 02:23: See an object's de Broglie wavelength depends on its momentum, so mass times velocity. 02:31: Higher momentum means a smaller wavelength. 02:37: ... tens of kilograms of thermal moving particles and have de Broglie wavelengths a couple of orders of magnitude smaller than the Planck ... 08:20: A particle resolves its location anywhere within the vicinity of its de Broglie wavelength. 08:59: This can look like an increase in the speed of light, but only within the uncertainty range defined by the de Broglie wavelength. 09:07: ... which is perhaps the deeper principle from which the de Broglie wavelength ... 01:46: This de Broglie Wavelength defines how well determined an object's position is. 02:23: See an object's de Broglie wavelength depends on its momentum, so mass times velocity. 02:37: ... tens of kilograms of thermal moving particles and have de Broglie wavelengths a couple of orders of magnitude smaller than the Planck ... 05:38: Remember the LEGO interferometer that discovered gravitational waves?
	2016-04-27: What Does Dark Energy Really Do? 01:33: During that expansion, it increases the wavelength of these electromagnetic waves, resulting in what we see as redshift, cosmological redshift.
	2016-04-06: We Are Star Stuff 09:27: ... spiral in as they radiate away their orbital energy in gravitational waves. ...
	2016-03-23: How Cosmic Inflation Flattened the Universe 02:26: They're defined by how fast sound waves could have traveled by the time the CMB was created.
	2016-03-09: Cosmic Microwave Background Challenge 04:18: This coming Monday, March, 14th, I'll be participating in a public seminar on the new LIGO discovery of gravitational waves. 04:29: If you're in the area and would like to attend, please RSVP to pbsspacetime@gmail.com with the subject line NYC Gravitational Waves. 04:42: You'll learn way more about gravitational waves than on any YouTube show. 04:18: This coming Monday, March, 14th, I'll be participating in a public seminar on the new LIGO discovery of gravitational waves. 04:29: If you're in the area and would like to attend, please RSVP to pbsspacetime@gmail.com with the subject line NYC Gravitational Waves. 04:42: You'll learn way more about gravitational waves than on any YouTube show.
	2016-02-24: Why the Big Bang Definitely Happened 06:16: We see ripples of sound waves in the pattern of those fluctuations. 08:40: ... ago, the LIGO team announced the very first detection of gravitational waves. ... 09:41: ... that Advanced LIGO was turned on just in time to catch the gravitational waves from the merger of black ... 11:39: ... quote Lawrence Stanley, "OK, but until the discovery of gravitational waves can lower my mortgage and reduce the price of gas at the pump, it ... 01:42: Light from distant galaxies is red shifted, stretched to longer wavelengths. 06:16: We see ripples of sound waves in the pattern of those fluctuations. 08:40: ... ago, the LIGO team announced the very first detection of gravitational waves. ... 09:41: ... that Advanced LIGO was turned on just in time to catch the gravitational waves from the merger of black ... 11:39: ... quote Lawrence Stanley, "OK, but until the discovery of gravitational waves can lower my mortgage and reduce the price of gas at the pump, it ...
	2016-02-17: Planet X Discovered?? + Challenge Winners! 03:37: The relativistic Doppler effect classically changes the wavelengths of light, blue-shifting approaching material and red-shifting receding material.
	2016-02-11: LIGO's First Detection of Gravitational Waves! 00:05: Gravitational waves have been directly detected for the very first time. 00:17: ... existence of these waves is the last major prediction of Einstein's theory of general relativity ... 00:49: ... predicted that it should certainly detect the passage of gravitational waves, of ripples in the fabric of spacetime caused by extreme gravitational ... 01:19: ... the detection, we put together a video explaining what gravitational waves are, how they're formed, and exactly how advanced LIGO detects ... 01:53: Any orbiting pair of massive objects generates gravitational waves. 01:57: ... through orbiting extremely close together, produce gravitational waves strong enough for us to detect, at the ... 02:30: But gravitational waves carry energy, which is sapped from the orbital energy of the system. 02:51: And so this was a very convincing but indirect verification of gravitational waves. 02:57: ... the waves produced when these stellar cores are still distant from each other are ... 04:26: Spacetime is stretched and squeezed as the wave passes by. 04:57: See, gravitational waves are inevitable if the theory is correct. 06:13: ... LIGO is sensitive to gravitational waves at frequencies produced by merging black holes and neutron stars, as ... 07:03: This is a really, really big deal, and it marks the beginning of the era of gravitational wave astronomy. 04:26: Spacetime is stretched and squeezed as the wave passes by. 00:05: Gravitational waves have been directly detected for the very first time. 00:17: ... existence of these waves is the last major prediction of Einstein's theory of general relativity ... 00:49: ... predicted that it should certainly detect the passage of gravitational waves, of ripples in the fabric of spacetime caused by extreme gravitational ... 01:19: ... the detection, we put together a video explaining what gravitational waves are, how they're formed, and exactly how advanced LIGO detects ... 01:53: Any orbiting pair of massive objects generates gravitational waves. 01:57: ... through orbiting extremely close together, produce gravitational waves strong enough for us to detect, at the ... 02:30: But gravitational waves carry energy, which is sapped from the orbital energy of the system. 02:51: And so this was a very convincing but indirect verification of gravitational waves. 02:57: ... the waves produced when these stellar cores are still distant from each other are ... 04:57: See, gravitational waves are inevitable if the theory is correct. 06:13: ... LIGO is sensitive to gravitational waves at frequencies produced by merging black holes and neutron stars, as ... 02:30: But gravitational waves carry energy, which is sapped from the orbital energy of the system. 02:57: ... the waves produced when these stellar cores are still distant from each other are far too ... 01:57: ... through orbiting extremely close together, produce gravitational waves strong enough for us to detect, at the ...
	2016-01-06: The True Nature of Matter and Mass 04:03: And then a pressure wave communications the force to the front until the whole spring is moving. 04:36: Photons in the photon box, but even in the spring, the density wave is ultimately communicated by electromagnetic interactions between the atoms. 04:46: That itself is a speed of light interaction, even if the resulting density wave isn't. 04:03: And then a pressure wave communications the force to the front until the whole spring is moving. 04:46: That itself is a speed of light interaction, even if the resulting density wave isn't.
	2015-12-16: The Higgs Mechanism Explained 08:49: Gareth Dean asks about this whole thing about using gravitational waves to turn up the core temperature of a star. 08:55: ... so gravitational waves carry a lot of energy, and some of it can get dumped into a star by ... 07:55: ... falls to the horizon, the light it emits is red shifted such long wavelengths that it effectively becomes ... 08:49: Gareth Dean asks about this whole thing about using gravitational waves to turn up the core temperature of a star. 08:55: ... so gravitational waves carry a lot of energy, and some of it can get dumped into a star by ...
	2015-12-09: How to Build a Black Hole 01:20: If you get impatient, you can turn up the core temperature by bombarding it with gravitational waves. 05:25: Certain numerical properties that you can assign to a particle exist in a wave of varying degrees of maybe. 01:20: If you get impatient, you can turn up the core temperature by bombarding it with gravitational waves.
	2015-10-28: Is The Alcubierre Warp Drive Possible? 06:23: ... like a mini version of the one being used to detect gravitational waves, To measure the tiny changes in path length created by a warp ... 07:09: ... next episode of "Space Time." Last week, we talked about gravitational waves, and whether the advanced LIGO Observatory has maybe seen ... 07:31: It'll be an orbiting gravitational wave observatory designed to detect much higher frequency gravitational waves than advanced LIGO. 08:01: ... this was the much hyped gravitational wave detection based on polarization anisotropies in the cosmic microwave ... 08:12: So now, the money is on the signal actually being due to dust, not G waves. 08:24: Now, MrSh1pman wants to know, if we find these G waves, will it change anything? 08:01: ... this was the much hyped gravitational wave detection based on polarization anisotropies in the cosmic microwave background ... 07:31: It'll be an orbiting gravitational wave observatory designed to detect much higher frequency gravitational waves than advanced LIGO. 06:23: ... like a mini version of the one being used to detect gravitational waves, To measure the tiny changes in path length created by a warp ... 07:09: ... next episode of "Space Time." Last week, we talked about gravitational waves, and whether the advanced LIGO Observatory has maybe seen ... 07:31: It'll be an orbiting gravitational wave observatory designed to detect much higher frequency gravitational waves than advanced LIGO. 08:12: So now, the money is on the signal actually being due to dust, not G waves. 08:24: Now, MrSh1pman wants to know, if we find these G waves, will it change anything?
	2015-10-22: Have Gravitational Waves Been Discovered?!? 00:03: Gravitational waves are the last prediction of Einstein's Theory of General Relativity. 01:03: However, there's one last, incredible prediction that has never been directly observed-- gravitational waves. 01:19: However, the analogy can give us a sense of what a gravitational wave really is. 01:37: Same deal with gravitational waves. 02:00: So a rotating sphere or a cylinder doesn't make waves. 02:08: ... a certain speed determined by the stiffness of the rubber, gravitational waves-- and indeed, gravity itself-- propagate according to the stiffness of ... 02:49: ... ripples on a pond or even electromagnetic waves-- which are all simple, up-down, longitudinal waves-- gravitational waves ... 03:11: Well, let's first think about all the sorts of things that might produce detectable gravitational waves. 03:42: And this change is for the most powerful waves that have likely ever passed through you. 04:07: And so it's no wonder that gravitational waves remain the only major prediction of GR without a direct measurement. 04:20: Gravitational waves carry energy. 05:21: ... paths just right, we can make the peaks of one of those electromagnetic waves line up with the valleys of the other, causing them to completely cancel ... 05:33: ... signal is seen, but if a gravitational wave passes by, it will shrink one of those paths and lengthen the other, and ... 06:12: So how do we tell that it's a gravitational wave? 06:22: It's even possible to get a direction for the wave by measuring the relative path lengths. 06:37: So how many g-m waves did LIGO find? 06:40: Well, between 2002 and 2010 when it ran, it found zero-- no gravitational waves at all. 07:58: Even if they spotted a wave, they'd keep it super-secret until they quadruple-checked results, which could take months. 05:33: ... signal is seen, but if a gravitational wave passes by, it will shrink one of those paths and lengthen the other, and then ... 00:03: Gravitational waves are the last prediction of Einstein's Theory of General Relativity. 01:03: However, there's one last, incredible prediction that has never been directly observed-- gravitational waves. 01:37: Same deal with gravitational waves. 02:00: So a rotating sphere or a cylinder doesn't make waves. 02:08: ... a certain speed determined by the stiffness of the rubber, gravitational waves-- and indeed, gravity itself-- propagate according to the stiffness of ... 02:49: ... ripples on a pond or even electromagnetic waves-- which are all simple, up-down, longitudinal waves-- gravitational waves ... 03:11: Well, let's first think about all the sorts of things that might produce detectable gravitational waves. 03:42: And this change is for the most powerful waves that have likely ever passed through you. 04:07: And so it's no wonder that gravitational waves remain the only major prediction of GR without a direct measurement. 04:20: Gravitational waves carry energy. 05:21: ... paths just right, we can make the peaks of one of those electromagnetic waves line up with the valleys of the other, causing them to completely cancel ... 06:37: So how many g-m waves did LIGO find? 06:40: Well, between 2002 and 2010 when it ran, it found zero-- no gravitational waves at all. 04:20: Gravitational waves carry energy. 02:49: ... even electromagnetic waves-- which are all simple, up-down, longitudinal waves-- gravitational waves are what we call quadrupole ... 04:07: And so it's no wonder that gravitational waves remain the only major prediction of GR without a direct measurement.
	2015-10-15: 5 REAL Possibilities for Interstellar Travel 12:26: Ed Stephan asks why we're even talking about gravitational waves when none have ever been observed. 12:32: ... in the meantime, in pointing out the indirect detection of gravitational waves, Garreth Dean delivers the amazing quote, "So we haven't seen a duck, but ... 12:26: Ed Stephan asks why we're even talking about gravitational waves when none have ever been observed. 12:32: ... in the meantime, in pointing out the indirect detection of gravitational waves, Garreth Dean delivers the amazing quote, "So we haven't seen a duck, but ...
	2015-10-07: The Speed of Light is NOT About Light 04:17: This transformation thing, it's like a mathy magic wand that you wave at your description of spacetime or your physical laws. 08:29: ... limit also happens to define the speed of propagation of electromagnetic waves-- the speed of ... 08:57: So lights or photons, also gravitational waves and gluons all have no mass. 08:29: ... limit also happens to define the speed of propagation of electromagnetic waves-- the speed of ... 08:57: So lights or photons, also gravitational waves and gluons all have no mass.
	2015-09-23: Does Dark Matter BREAK Physics? 09:36: In fact, in the vicinity of the black hole, this radiation is poorly localized, having a wavelength of all of the Schwarzschild radius.
	2015-08-05: What Physics Teachers Get Wrong About Tides! 08:47: ... how Miller's planet in the movie "Interstellar" could've had such a huge waves without the astronauts themselves being stretched or ...
	2015-06-24: The Calendar, Australia & White Christmas 06:16: ... McLean asked, "if aliens can't pick up our radio waves, then why are we trying to listen for alien radio waves with SETI?" Well, ...
	2015-05-27: Habitable Exoplanets Debunked! 03:54: ... from that of its star and see how bright that light is at different wavelengths. ... 04:01: That graph of brightness versus wavelength is called an object's spectrum. 04:05: Since different atoms and molecules emit or absorb particular wavelengths of light only, the spectrum tells you a lot about atmospheric composition. 03:54: ... from that of its star and see how bright that light is at different wavelengths. ... 04:05: Since different atoms and molecules emit or absorb particular wavelengths of light only, the spectrum tells you a lot about atmospheric composition.
	2015-03-25: Cosmic Microwave Background Explained 01:46: It's emitting electromagnetic waves of all wavelengths. 03:16: And just like toasters, people and tacos, it was emitting a thermal distribution of electromagnetic waves. 01:46: It's emitting electromagnetic waves of all wavelengths. 01:49: Moreover, the intensity at different wavelength is in very specific proportions that trace out a graph very close to this. 02:04: Now, everything has a temperature, so everything has a thermal spectrum, and it emits all electromagnetic wavelengths. 02:21: ... to 2.7 degrees above absolute zero, the peak shifts way into microwave wavelengths and, lo and behold, exactly matches the CNB, and I mean ... 04:28: ... a prior episode that you can revisit here, expanding space stretches the wavelength of free streaming light through a process called cosmological ... 04:37: ... orangey thermal spectrum of light was redshifted to longer and longer wavelengths, becoming toaster read and eventually infra-red, so that to human eyes, ... 01:46: It's emitting electromagnetic waves of all wavelengths. 02:04: Now, everything has a temperature, so everything has a thermal spectrum, and it emits all electromagnetic wavelengths. 02:21: ... to 2.7 degrees above absolute zero, the peak shifts way into microwave wavelengths and, lo and behold, exactly matches the CNB, and I mean ... 04:37: ... orangey thermal spectrum of light was redshifted to longer and longer wavelengths, becoming toaster read and eventually infra-red, so that to human eyes, ... 01:46: It's emitting electromagnetic waves of all wavelengths. 03:16: And just like toasters, people and tacos, it was emitting a thermal distribution of electromagnetic waves.
	2015-02-25: How Do You Measure the Size of the Universe? 00:55: That's the part that we, in principle, can see with light or gravitational waves. 03:22: In more extreme cases, the wavelength can be stretched out of the visible spectrum altogether, into microwaves or radio waves. 03:02: Light has a color determined by its wavelength. 03:04: Longer wavelength light is redder, shorter bluer. 03:14: But because space is expanding, the wavelength of light gets stretched as it travels to us, making the blue light red; hence, the term redshift. 03:22: In more extreme cases, the wavelength can be stretched out of the visible spectrum altogether, into microwaves or radio waves. 03:42: And thus, it has its wavelength stretched more. 03:04: Longer wavelength light is redder, shorter bluer. 03:42: And thus, it has its wavelength stretched more. 00:55: That's the part that we, in principle, can see with light or gravitational waves. 03:22: In more extreme cases, the wavelength can be stretched out of the visible spectrum altogether, into microwaves or radio waves.

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