Search PBS Space Time

What are you looking for?

	2022-11-09: What If Humanity Is Among The First Spacefaring Civilizations? 17:23: ... in which the wavefunction appears to change everywhere at the instant a measurement is made, in apparent violation of relativity and the speed of light ... 18:13: Benjamin Shropshire asks if anyone has ruled out hidden influences traveling from the measurement back in time to the creation of the entangled state. 19:08: ... asks if there’s a problem using a random number generator to decide measurement direction, considering that true randomness is ... 19:36: ... require a pretty complicated conspiracy of influences connecting every measurement device with every potential measurement subject, and I’ve never heard a ... 19:08: ... asks if there’s a problem using a random number generator to decide measurement direction, considering that true randomness is ... 19:36: ... of influences connecting every measurement device with every potential measurement subject, and I’ve never heard a good description of how the details ...
	2022-10-26: Why Did Quantum Entanglement Win the Nobel Prize in Physics? 02:13: Each ball is in a superposition state of maybe black-maybe white until a measurement is made. 04:54: ... if those properties  really are decided at the moment of measurement. ... 07:09: ... quantum mechanics says that those polarizations are undefined until measurement, when they will always turn out  to be opposite to each ... 07:56: ... result of a quantum measurement depends on how you make the measurement - in the case of this ... 08:35: ... the photons might carry hidden information about the eventual measurement direction the whole time and sort of conspire to look like standard ... 08:47: To close this loophole it would be necessary to somehow set the measurement direction after the photons were produced. 09:22: ... order to change the measurement direction of a polarizer you have to rotate it, but it’s kinda hard ... 10:46: The first I already mentioned: what if the choice of measurement is not independent of the creation of the entangled particles? 11:16: ... but also with the random number generator or the physicist choosing the measurement direction,   so ultimately the universe has no  choice ... 16:23: ... we’ll be trying to send actual images rather than simple numerical  measurements and status ... 07:56: ... result of a quantum measurement depends on how you make the measurement - in the case of this experiment, the orientation of the polarizers ... 08:35: ... the photons might carry hidden information about the eventual measurement direction the whole time and sort of conspire to look like standard quantum ... 08:47: To close this loophole it would be necessary to somehow set the measurement direction after the photons were produced. 11:16: ... but also with the random number generator or the physicist choosing the measurement direction,   so ultimately the universe has no  choice but to always hide the ... 09:22: ... order to change the measurement direction of a polarizer you have to rotate it, but it’s kinda hard to do that faster ... 09:33: Aspect found a way to randomize measurement direction without moving the polarizers at all. The trick was to use a type of transducer. 08:08: Bell’s theorem assumes the choice of measurement is completely free and independent of the particle creation process. 16:23: ... we’ll be trying to send actual images rather than simple numerical  measurements and status ...
	2022-10-12: The REAL Possibility of Mapping Alien Planets! 01:25: ... repeat this trick with visible light  because this requires exact measurement of the   arrival time and phase of the electromagnetic ...
	2022-09-28: Why Is 1/137 One of the Greatest Unsolved Problems In Physics? 02:22: ... our measurement apparatus improved, we saw  that the single spectral lines were ... 09:43: The problem is, most of these constants  require you to choose units of measurement. 02:22: ... our measurement apparatus improved, we saw  that the single spectral lines were actually a ...
	2022-09-14: Could the Higgs Boson Lead Us to Dark Matter? 12:38: The error bars on this measurement are still large, and so we need to watch more Higgs bosons decay.
	2022-08-17: What If Dark Energy is a New Quantum Field? 04:47: ... yeah, and it’s pretty much … -1, the default option. Our most precise measurement comes from Planck satellite data, which mapped the cosmic microwave ... 06:25: ... universe we get a different number. The latter is from Planck satellite measurements of the cosmic microwave background. The current thinking is that one of ... 13:27: ... fully operational James Webb Space Telescope will help by pushing our measurements of the expansion rate back billions of years from the current supernova ... 06:25: ... expansion rate should have evolved into the late universe. The Planck measurement assumes a constant dark energy and an unchanging omega of -1. But if dark energy ... 13:27: ... fully operational James Webb Space Telescope will help by pushing our measurements of the expansion rate back billions of years from the current supernova ...
	2022-08-03: What Happens Inside a Proton? 16:44: ... the spins  measured for one electron and the choice   of measurement axis used on its entangled partner that is the subject of the Bell ... 18:44: ... partner then you know what its spin is. However that measurement isn't a passive act - you will   have actually forced the ... 16:44: ... the spins  measured for one electron and the choice   of measurement axis used on its entangled partner that is the subject of the Bell test ... 18:44: ... partner then you know what its spin is. However that measurement isn't a passive act - you will   have actually forced the electron’s ... 16:44: ... defined by your choice of experimental axis at the moment of measurement. You’ll always measure fully-up or fully-down,   no matter what ...
	2022-07-20: What If We Live in a Superdeterministic Universe? 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. 03:27: Measurement of one electron would influence the other in a very real way - something Einstein referred to as spooky action at a distance. 04:02: According to standard quantum mechanics, that spin is undefined until measurement. 04:06: Upon measurement it will become fixed along the axis of the measurement device. 04:37: A horizontal measurement will yield a 50-50 chance of being left or right for his down-pointing electron. 04:51: ... they’ll notice certain peculiar correlations between their choices of measurement axis and the other’s measured ... 06:01: The scientists go off and make their own choices for their measurement directions. 06:10: When the two compare results, they will see correlations between the spin measurements because the original spin directions were correlated. 06:17: But there’s no correlation between one scientist’s measurement results and the other scientist’s choice of measurement direction. 09:22: The Bell test results are weird because Bob’s measurements turn out to be inexplicably correlated with Alice’s choices. 10:02: That’s the statistical independence of the measurements. 10:24: ... between Alice and Bob’s supposedly free decisions of how they make their measurements, and the states of the measured ... 11:45: To close the loophole, a Bell test needs to be performed where the choice of measurement direction is truly statistically independent. 12:08: ... we can at least do a Bell test where the “deciders” and the measurement subjects have past light cones that intersect with each other as far ... 12:35: ... that light was used in place of a random number generator to decide the measurement orientation in the Bell ... 13:43: ... lock-step determinism in a way that preserves correlations between measurement subject and ... 04:51: ... they’ll notice certain peculiar correlations between their choices of measurement axis and the other’s measured ... 02:39: We say that measurement “collapses” the wavefunction, obliterating all potential results in favor of one actual result. 04:06: Upon measurement it will become fixed along the axis of the measurement device. 06:17: But there’s no correlation between one scientist’s measurement results and the other scientist’s choice of measurement direction. 11:45: To close the loophole, a Bell test needs to be performed where the choice of measurement direction is truly statistically independent. 06:01: The scientists go off and make their own choices for their measurement directions. 12:35: ... that light was used in place of a random number generator to decide the measurement orientation in the Bell ... 13:43: ... lock-step determinism in a way that preserves correlations between measurement subject and ... 12:08: ... we can at least do a Bell test where the “deciders” and the measurement subjects have past light cones that intersect with each other as far back in the ... 02:33: The results of your measurements are plucked from the wavefunction of whatever you’re observing. 06:10: When the two compare results, they will see correlations between the spin measurements because the original spin directions were correlated. 09:22: The Bell test results are weird because Bob’s measurements turn out to be inexplicably correlated with Alice’s choices. 10:02: That’s the statistical independence of the measurements. 10:24: ... between Alice and Bob’s supposedly free decisions of how they make their measurements, and the states of the measured ... 09:22: The Bell test results are weird because Bob’s measurements turn out to be inexplicably correlated with Alice’s choices.
	2022-06-01: What If Physics IS NOT Describing Reality? 04:56: ... is the spin up or down relative to the direction  of measurement? We ask this question with a Stern   Gerlach apparatus, where ... 08:49: ... from a quantum wavefunction. For  example, that the product of the measurement error   in a particle’s position and momentum has to be  ... 05:53: ... information about its spin  in that direction. And following that measurement,   the left-right alignment of the spin has become  defined - after ... 07:23: ... learn the spin direction of  both particles. And in making that measurement,   you’ve forced the single bit of spin information  in both electrons ...
	2022-04-27: How the Higgs Mechanism Give Things Mass 16:02: ... -  but that’s for another time. But what about   this new measurement of the W boson mass? Mass  results from interaction with the Higgs ...
	2022-04-20: Does the Universe Create Itself? 00:59: ... and quantum mechanics. In quantum mechanics, not only does the act of measurement profoundly influence the thing being measured, but it seems we can’t ... 07:08: ... really does exist in a superposition of all possible states until the measurement is made, and the choice of that measurement can be made after the ... 07:43: ... a pair of entangled particles - the choice of the direction of the spin measurement seems to have an instantaneous influence on its partner, even if that ... 12:05: ... time two particles bump together and become entangled we have an act of measurement. If this all seems a little vague and wishy washy, it’s because it is. ... 00:59: ... and quantum mechanics. In quantum mechanics, not only does the act of measurement profoundly influence the thing being measured, but it seems we can’t even assign ...
	2022-03-16: What If Charge is NOT Fundamental? 02:30: ... corresponding to the spin axis being aligned or anti-aligned with your measurement device, which we’ll call “up” and “down” ...
	2022-03-08: Is the Proxima System Our Best Hope For Another Earth? 08:18: Followup observations in January this year somewhat solidified the measurements of Proxima D.
	2022-02-16: Is The Wave Function The Building Block of Reality? 01:06: ... example when we make a measurement of a particle, the property that we’re measuring seems to be plucked ... 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. 05:09: ... different parts of the wave function corresponding to different possible measurement results to evolve independently of each other. Another thing about the ... 06:53: ... necessarily means bringing lots of particles into the picture - in the measurement device and in your own brain. With enough particles collapse becomes ... 10:48: ... Experiments are approaching the masses necessary to make such direct measurements, but they’re not quite there ... 11:50: ... of copper and lead. With such pristine conditions for a high-precision measurement, the scientists in Trieste were able to measure single photons emitted ... 06:53: ... necessarily means bringing lots of particles into the picture - in the measurement device and in your own brain. With enough particles collapse becomes ... 10:48: ... Experiments are approaching the masses necessary to make such direct measurements, but they’re not quite there ...
	2021-12-10: 2021 End of Year AMA! 00:02: ... the quantum world sort of makes a decision uh uh in the sense of a measurement being made and say an electron having to choose one position or ...
	2021-10-13: New Results in Quantum Tunneling vs. The Speed of Light 02:52: ... measurement, or upon interaction with another particle, the proton can end up ... 07:08: ... that wavefunction can’t travel faster than the speed of light, but upon measurement, the particle may appear to be at the leading edge of its wavefunction - ...
	2021-10-05: Why Magnetic Monopoles SHOULD Exist 04:37: ... that the equations of quantum mechanics had a particular symmetry - the measurements they predict are unaltered by changes in one simple property - the phase ...
	2021-09-21: How Electron Spin Makes Matter Possible 08:21: ... never, ever observe Psi - all we can do is map Psi^2 by making multiple measurements. The unobservability of Psi is critical to this whole explanation, so ...
	2021-08-18: How Vacuum Decay Would Destroy The Universe 09:38: ... can determine the shape of the Higgs field with   precise measurements of the particles  that gain their mass from the Higgs.   ...
	2021-08-10: How to Communicate Across the Quantum Multiverse 02:29: ... which says that the wavefunction collapses at the point of measurement, leaving only one reality; or de Broglie-Bohm pilot wave theory, which ... 03:30: ... changes over space and time - and so it should completely determine the measurements we can make of that quantum system. But if our observations are 100% ... 07:14: ... could give a way to explore what happens to the wavefunction after measurement. Does it vanish as Copenhagen demands, or persist as many worlds would ... 08:08: ... way. You can only detect that the influence happened by comparing the measurement statistics of multiple entangled pairs - and to do that you need to send ... 09:57: ... call them up or down. In the many-worlds interpretation, by making that measurement you just split the world in two and you split yourself. In one world you ... 02:29: ... which says that the wavefunction collapses at the point of measurement, leaving only one reality; or de Broglie-Bohm pilot wave theory, which says that ... 08:08: ... way. You can only detect that the influence happened by comparing the measurement statistics of multiple entangled pairs - and to do that you need to send regular, ... 03:30: ... changes over space and time - and so it should completely determine the measurements we can make of that quantum system. But if our observations are 100% ...
	2021-08-03: How An Extreme New Star Could Change All Cosmology 05:39: ... with our measurements for temperature and brightness, we get a radius for Zee of 2140 ... 11:52: ... there does seem to be a disagreement between the supernova dark energy measurements and the measurements from the cosmic microwave background - again, ... 05:39: ... with our measurements for temperature and brightness, we get a radius for Zee of 2140 ... 11:52: ... there does seem to be a disagreement between the supernova dark energy measurements and the measurements from the cosmic microwave background - again, ...
	2021-07-21: How Magnetism Shapes The Universe 15:28: ... that for every measurement of a spin-1/2 state we get 2 worlds, but for every measurement of photon ...
	2021-07-13: Where Are The Worlds In Many Worlds? 04:04: ... measurements appear to be randomly selected based on the current state of the ... 04:16: We never see the wavefunction - we only see measurements - we pluck our reality from this fantastically complex structure. 05:22: ... - it instantaneously shrinks from encompassing a huge range of possible measurement outcomes to encompassing only the outcome that was measured - and that ... 08:14: ... no way to make a perfectly reliable measurement without corrupting the phase of the wavefunction in a way that destroys ... 05:22: ... - it instantaneously shrinks from encompassing a huge range of possible measurement outcomes to encompassing only the outcome that was measured - and that value is ... 04:04: ... measurements appear to be randomly selected based on the current state of the ... 04:16: We never see the wavefunction - we only see measurements - we pluck our reality from this fantastically complex structure.
	2021-07-07: Electrons DO NOT Spin 03:48: ... assume electrons have a maximum possible size given by the best  measurements of the day, then their surfaces would have to be moving faster than ...
	2021-06-23: How Quantum Entanglement Creates Entropy 03:45: ... precisely the amount of information we can hope to gain by making a measurement on the system.   If all the particles are bunched up in the ... 05:55: ... information we can get out of   the system when we make a measurement. But perhaps the most interesting - von   Neumann entropy tells us ...
	2021-06-16: Can Space Be Infinitely Divided? 07:10: ... any further decrease in photon wavelength actually increases your measurement   uncertainty due to the warping of space. So this is one way of ...
	2021-05-25: What If (Tiny) Black Holes Are Everywhere? 13:36: ... at how the Heisenberg uncertainty principle can be gamed to improve measurements - in particular in gravitational wave ...
	2021-05-19: Breaking The Heisenberg Uncertainty Principle 00:25: ... is good to to one part in a billion And also pretty recently we have the measurement of gravitational waves by ... 00:47: ... measurements have become so precise that we’re starting to run up against the ... 01:05: Today we’re going to see how the uncertainty principle can be hacked to make measurements more precisely than should ever be possible. 01:36: Exact measurement of its energy means its location in time is blurred. 02:37: ... which would account for a greater uncertainty in its momentum after the measurement. ... 02:56: Basically, he thought the uncertainty principle arose as a result of the measurement disturbing the system. 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. 09:56: The use of squeezed light is just one example of how quantum mechanics can be used to increase measurement precision. 10:17: ... the limit beyond what we thought possible to force ever more certain measurements of this uncertain space ... 02:56: Basically, he thought the uncertainty principle arose as a result of the measurement disturbing the system. 09:56: The use of squeezed light is just one example of how quantum mechanics can be used to increase measurement precision. 00:47: ... measurements have become so precise that we’re starting to run up against the ... 01:05: Today we’re going to see how the uncertainty principle can be hacked to make measurements more precisely than should ever be possible. 10:17: ... the limit beyond what we thought possible to force ever more certain measurements of this uncertain space ...
	2021-04-07: Why the Muon g-2 Results Are So Exciting! 02:22: QED predicts the value for the electrons g-factor that matches experimental measurements to one part in a billion. 02:44: Starting in 20 years ago, experimental measurements of the Muon g-factor did not agree with the QED calculation. 06:52: For the electron, the current measurement is precise to one part in a billion. 09:00: Prior to this experiment, various labs over the past 20 years have refined the Muon g-factor measurement. 11:10: ... course this was a systematic error, some unknown factor influencing the measurement that is not a new particle, the g-2 team worked very hard to rule ... 11:20: But the only way to be sure is to repeat the measurement with a new independent experiment. 02:22: QED predicts the value for the electrons g-factor that matches experimental measurements to one part in a billion. 02:44: Starting in 20 years ago, experimental measurements of the Muon g-factor did not agree with the QED calculation.
	2021-03-23: Zeno's Paradox & The Quantum Zeno Effect 07:02: ... to the researchers, the laser acts like a measurement - and remember, measurement should be able to freeze quantum arrows and ... 07:23: In theory, if these “measurements” are fast enough they should stop the wavefunction from evolving. 08:29: ... physicist Leslie Ballentine argued that it’s not the abstract act of measurement that causes the quantum Zeno effect, but rather it’s a physical ... 08:43: ... the very foundations of quantum mechanics: what exactly do we mean by a “measurement” and what do we mean by wavefunction ... 08:54: Let’s start with measurement. 08:55: ... never possible to perform a measurement without interacting with a system, and that interaction has consequences ... 09:04: If the measurement interaction is subtle enough then you might hope to gain that info without perturbing the system too much. 09:21: ... the atom with many, many photons - and that was certainly not a “subtle” measurement. ... 09:30: ... Washington University claim to have proved that it’s perturbation, not measurement, that causes the quantum Zeno effect by demonstrating that with the right ... 09:50: Another way to think about measurement is in terms of how much information it extracts from the system. 09:55: ... idea is that measurement causes wavefunction collapse because it scrambles the delicate ... 10:52: In the Copenhagen interpretation, only the part of the wavefunction corresponding to the measurement outcome survives. 12:10: And perhaps some of this is just semantic - for example, how do we really define measurement and interaction? 13:40: ... clarification, pointing out that that the CMB number isn't actually a "measurement" of the current rate of expansion - which of course it can't be because ... 14:22: ... therefore be resolved by finding an error in either the CMB or supernova measurements, but also by finding one of the assumptions in the CMB calculation is ... 07:02: ... to the researchers, the laser acts like a measurement - and remember, measurement should be able to freeze quantum arrows and ... 09:04: If the measurement interaction is subtle enough then you might hope to gain that info without perturbing the system too much. 10:52: In the Copenhagen interpretation, only the part of the wavefunction corresponding to the measurement outcome survives. 07:23: In theory, if these “measurements” are fast enough they should stop the wavefunction from evolving. 14:22: ... therefore be resolved by finding an error in either the CMB or supernova measurements, but also by finding one of the assumptions in the CMB calculation is ...
	2021-03-16: The NEW Crisis in Cosmology 00:22: ... we have two extremely careful, increasingly precise measurements of how fast the universe   is expanding which should agree ... 02:07: ... the redshifts. It depends   on a long chain of distance measurements that we call the cosmic distance ladder. First you ... 02:36: ... distance measurements were based on a method pioneered by Henrietta Swan ... 03:55: ... With its discovery it suddenly became VERY important to perfect our measurements of the   expansion rate - both to confirm dark ... 06:22: ... a giant space ruler. Ultimately, refining the supernova distance measurements comes   down to refining parallax measurements,  and ... 08:03: ... so it was that in 1912 Henrietta Swan Leavitt used parallax measurements of Cepheids in the   Milky Way to turn these stars into ... 10:40: ... time delay in these flickering lenses, we can   get a measurement of cosmic distances, and with that a measurement of the expansion ... 03:55: ... story splits. There are, broadly, two approaches to improving that measurement.   One is to double down on the old method - find more type 1a ... 00:22: ... we have two extremely careful, increasingly precise measurements of how fast the universe   is expanding which should agree ... 02:07: ... the redshifts. It depends   on a long chain of distance measurements that we call the cosmic distance ladder. First you ... 02:36: ... distance measurements were based on a method pioneered by Henrietta Swan ... 03:55: ... With its discovery it suddenly became VERY important to perfect our measurements of the   expansion rate - both to confirm dark ... 06:22: ... a giant space ruler. Ultimately, refining the supernova distance measurements comes   down to refining parallax measurements,  and ... 08:03: ... so it was that in 1912 Henrietta Swan Leavitt used parallax measurements of Cepheids in the   Milky Way to turn these stars into ... 06:22: ... a giant space ruler. Ultimately, refining the supernova distance measurements comes   down to refining parallax measurements,  and that’s what we’ve ... 08:03: ... few Cepheids that are close enough for   parallax measurements. Things started to get better when we put telescopes in space - ... 06:22: ... distance measurements comes   down to refining parallax measurements,  and that’s what we’ve finally ... 08:03: ... effect of Earth’s atmosphere it’s possible to make better position measurements.   The Hubble Space Telescope has done great work here, and so has the ...
	2021-01-12: What Happens During a Quantum Jump? 01:02: That proof required precision measurements that didn’t exist in Schrodinger’s time. 02:55: ... says that “measurement collapses the wavefunction”, which these days is more often taken to ... 11:27: It's to do with how strongly the system is coupled to the measurement apparatus. 11:31: The weaker the measurement, the less likely a true quantum jump is to occur. 11:27: It's to do with how strongly the system is coupled to the measurement apparatus. 02:55: ... says that “measurement collapses the wavefunction”, which these days is more often taken to mean that ... 01:02: That proof required precision measurements that didn’t exist in Schrodinger’s time.
	2020-12-15: The Supernova At The End of Time 15:25: ... you CANNOT reverse time in the double slit experiment, because after the measurement of particle position is made, the state of the wavefunction before that ...
	2020-12-08: Why Do You Remember The Past But Not The Future? 03:29: Actually, not really - perfect measurement isn’t really possible, even assuming all the necessary information was still inside the rock.
	2020-11-11: Can Free Will be Saved in a Deterministic Universe? 08:16: ... practice, because unknown random processes are at work, and/or perfect measurement is not possible for any entity that could possibly ...
	2020-10-20: Is The Future Predetermined By Quantum Mechanics? 04:23: ... defined by the equations of quantum mechanics but at the moment of measurement, a single reality is randomly selected from the distribution of possible ...
	2020-07-28: What is a Theory of Everything: Livestream 00:00: ... really nailing down the cosmological constant really doing precision measurements in all different types of lower energy machines right because the ...
	2020-07-20: The Boundary Between Black Holes & Neutron Stars 08:43: ... direct measurements of neutron star masses come from pulsars - cosmic lighthouses that ...
	2020-07-08: Does Antimatter Explain Why There's Something Rather Than Nothing? 08:50: ... the more tests they can conduct on it, and so the more precise their measurements will ... 10:18: In a recent measurement, ALPHA's been able to test CPT invariance down to 16 parts per billion. So far no evidence of CPT violation. 10:39: ... in their trap. They expect this to dramatically improve their measurement ... 10:18: In a recent measurement, ALPHA's been able to test CPT invariance down to 16 parts per billion. So far no evidence of CPT violation. 10:39: ... in their trap. They expect this to dramatically improve their measurement precision. ... 08:50: ... the more tests they can conduct on it, and so the more precise their measurements will ...
	2020-06-08: Can Viruses Travel Between Planets? 15:01: ... you need to factor in the Casimir force between them to get an accurate measurement of the gravitational ...
	2020-05-27: Does Gravity Require Extra Dimensions? 08:02: But Mitchell died before he could conduct the experiment, and so Cavendish inherited and improved the device, and actually made the measurement. 08:55: ... and by reading off the amount of rotation Cavendish made the first measurement of the gravitational ... 09:42: His measurement remained the most precise for over 100 years. 09:47: ... the beginning of a grand tradition in physics of making high-precision measurements to learn about the fundamental nature of the ... 10:33: These incredible advances have led to a modern measurement with 6 digits of precision. 11:19: The inverse square law seems to hold down to the current limits of our measurements. 09:42: His measurement remained the most precise for over 100 years. 09:47: ... the beginning of a grand tradition in physics of making high-precision measurements to learn about the fundamental nature of the ... 11:19: The inverse square law seems to hold down to the current limits of our measurements.
	2020-04-28: Space Time Livestream: Ask Matt Anything 00:00: ... not say one word when zero words would do there was also a unit of measurements in in Cambridge for the rate of speech where one Dirac equaled one ...
	2020-03-16: How Do Quantum States Manifest In The Classical World? 03:37: ... spin depends on how you choose to measure it - it depends on your “measurement basis.” And a well defined spin direction in one basis can be expressed ... 05:32: ... if I measure the spin of one particle - say the electron - my choice of measurement basis defines the spin of the positron. If I measure the electron in the ... 08:44: ... the atom’s state, which would influence the electron and positron. The measurement hasn't actually happened yet. The wave function hasn't collapsed. Here’s ... 09:56: ... so our atomic measurement device doesn’t “collapse the wavefunction.” It doesn't settle ... 10:53: ... this information if you could perfectly measure all particles in your measurement device. But eventually this entanglement cascade reaches the surrounding ... 11:11: ... this entanglement web. These are properties of the quantum system - measurement bases - whose information is relatively simply reflected throughout the ... 13:22: ... should say none of this fully solves the measurement problem it only tells us why certain quantum states are observable on ... 13:47: ... object positions, feline mortality statuses, even the results of quantum measurements - do NOT exist in the underlying quantum objects. Quantum objects remain ... 17:40: ... interpretation states that only one branch of the wavefunction survives measurement, corresponding to one possible result of that measurement. And the ... 11:11: ... this entanglement web. These are properties of the quantum system - measurement bases - whose information is relatively simply reflected throughout the ... 03:37: ... spin depends on how you choose to measure it - it depends on your “measurement basis.” And a well defined spin direction in one basis can be expressed as a ... 05:32: ... if I measure the spin of one particle - say the electron - my choice of measurement basis defines the spin of the positron. If I measure the electron in the ... 09:56: ... device doesn’t “collapse the wavefunction.” It doesn't settle measurement basis. So where does that happen? In order for us to be aware of a measurement ... 05:32: ... if I measure the spin of one particle - say the electron - my choice of measurement basis defines the spin of the positron. If I measure the electron in the vertical ... 09:56: ... so our atomic measurement device doesn’t “collapse the wavefunction.” It doesn't settle measurement ... 10:53: ... this information if you could perfectly measure all particles in your measurement device. But eventually this entanglement cascade reaches the surrounding ... 09:56: ... so our atomic measurement device doesn’t “collapse the wavefunction.” It doesn't settle measurement basis. So ... 13:22: ... should say none of this fully solves the measurement problem it only tells us why certain quantum states are observable on ... 17:40: ... The Many Worlds interpretation states that all branches survive, and the measurement result that we observe depends on which branch we find ourselves in. However ... 13:47: ... object positions, feline mortality statuses, even the results of quantum measurements - do NOT exist in the underlying quantum objects. Quantum objects remain ...
	2020-03-03: Does Quantum Immortality Save Schrödinger's Cat? 00:39: ... same time, to having only one clear observable state at the moment of measurement? ... 00:51: This is the measurement problem. 01:01: ... something very important: by itself, decoherence does NOT solve the measurement ... 01:29: ... branches that we don’t observe somehow vanish at the moment of measurement. ... 11:51: ... and on quantum decoherence as a better path to understanding the measurement ... 00:51: This is the measurement problem. 01:01: ... something very important: by itself, decoherence does NOT solve the measurement problem. ... 11:51: ... and on quantum decoherence as a better path to understanding the measurement problem. ...
	2020-02-24: How Decoherence Splits The Quantum Multiverse 00:35: ... last week’s episode we started down this rabbit hole exploring the measurement problem - the question of why and where the blurry quantum wavefunction ... 01:03: The upshot is that more and more physicists think that consciousness - and even measurement - don’t directly cause wavefunction collapse. 01:52: ... the distribution of possible outcomes if you were to try to make a measurement of that ... 09:11: Any measurement device must introduce some level of decoherence to the wavefunction before it reaches the screen. 14:12: Nor is it accepted that decoherence fully explains the measurement problem and wavefunction collapse. 01:03: The upshot is that more and more physicists think that consciousness - and even measurement - don’t directly cause wavefunction collapse. 09:11: Any measurement device must introduce some level of decoherence to the wavefunction before it reaches the screen. 00:35: ... last week’s episode we started down this rabbit hole exploring the measurement problem - the question of why and where the blurry quantum wavefunction ... 14:12: Nor is it accepted that decoherence fully explains the measurement problem and wavefunction collapse. 00:35: ... last week’s episode we started down this rabbit hole exploring the measurement problem - the question of why and where the blurry quantum wavefunction collapses ...
	2020-02-18: Does Consciousness Influence Quantum Mechanics? 01:42: ... tells us that the very act of measurement or observation causes an experiment to settle on a particular result, ... 03:05: The Copenhagen interpretation states that, prior to measurement, it’s meaningless to talk about a real, physical state for the electron. 03:12: It exists only as the possible outcome of a future measurement. 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 ... 04:46: ... measuring apparatus and the conscious awareness of the result of that measurement. ... 05:49: We call this open question the Measurement Problem. 08:02: Wigner and von Neumann weren’t the only ones who questioned the relationship between the mind and the Measurement Problem. 10:41: ... that the wavefunction collapse must be a continuous process between the measurement device and the conscious mind - and definitely not a sudden event caused ... 12:09: ... not having settled the Measurement Problem - at least not with full consensus, modern quantum theory has ... 10:41: ... that the wavefunction collapse must be a continuous process between the measurement device and the conscious mind - and definitely not a sudden event caused by the ... 05:49: We call this open question the Measurement Problem. 08:02: Wigner and von Neumann weren’t the only ones who questioned the relationship between the mind and the Measurement Problem. 12:09: ... not having settled the Measurement Problem - at least not with full consensus, modern quantum theory has come a ...
	2020-02-11: Are Axions Dark Matter? 03:02: ... and negative charges - an electric dipole field. Our very sensitive measurements have found that no such field exists- or if it is there then it’s a ...
	2020-01-06: How To Detect a Neutrino 06:24: ♪ ♪ We can use our measurement to determine how much oscillation has occurred.
	2019-12-09: The Doomsday Argument 14:06: ... slight positive or negative curvature just beyond the sensitivity of our measurement. ...
	2019-12-02: Is The Universe Finite? 02:06: ... today - particularly the modern expansion rate determined from supernova measurements. ... 04:46: ... always a degree of uncertainty due to the imperfect nature of any measurement. ... 11:51: The tension between the Planck results and other cosmological measurements seems to be growing. 12:30: ... them to construct equations of motion, laws of physics, and systems of measurement based on the algebra of quantum ... 02:06: ... today - particularly the modern expansion rate determined from supernova measurements. ... 11:51: The tension between the Planck results and other cosmological measurements seems to be growing.
	2019-10-15: Loop Quantum Gravity Explained 03:54: Certain properties have an in-built uncertainty and only take concrete values after measurement. 04:00: Absent measurement, they exist in a fuzzy space of possibilities called a wavefunction.
	2019-07-25: Deciphering The Vast Scale of the Universe 04:36: ... Andromeda Nebula became the Andromeda galaxy and with more distance measurements it became clear that all spiral nebulae were island universes of their ...
	2019-07-15: The Quantum Internet 06:23: To send that message, Bill performs a particular type of measurement on his qubits called a Bell measurement - not a 'Bill' measurement. 06:32: ... this measurement simultaneously on A and C entangles these qubits but breaks the ... 07:03: Now Bill takes photon A and entangles it with photon C using a Bell measurement so that now A and C have opposite polarization. 07:44: This measurement outcome is encoded in two classical bits which Bill sends to Ted along the classical channel. 07:50: ... the information in these two bits Ted can then calibrate a measurement of his own qubit B, after which that qubit will be in the state qubit C ... 08:01: ... are only using photonic qubits then it's not so easy to perform a Bell measurement that will give all of the information we need for this final step, but ... 08:54: It’s pretty much impossible to do all the transmissions, entanglements, and measurements in perfect synchrony. 09:45: ... qubits, which they could use to communicate by exchanging classical Bell measurement ... 06:23: To send that message, Bill performs a particular type of measurement on his qubits called a Bell measurement - not a 'Bill' measurement. 09:45: ... qubits, which they could use to communicate by exchanging classical Bell measurement data. ... 07:44: This measurement outcome is encoded in two classical bits which Bill sends to Ted along the classical channel. 06:32: ... this measurement simultaneously on A and C entangles these qubits but breaks the entanglement between A ... 08:54: It’s pretty much impossible to do all the transmissions, entanglements, and measurements in perfect synchrony.
	2019-05-09: Why Quantum Computing Requires Quantum Cryptography 08:51: If someone... not Eve ... Werner, intercepted these messages, which were after all sent on a public channel, and did his own measurements. 09:37: Once they have done this test and verified that the information wasn’t intercepted, they discard the non-matching measurements and keep the rest. 11:18: Our choice of measurement direction will set the diection of those spin or polarizations axes. 11:45: ... in a different basis to its entangled partner, the results of the measurements will be correlated in a way that depends on the choice of measurement ... 12:23: Because they’re entangled, the outcome of Alberts and Niels measurements should be correlated in a very particular way defined by Bell’s theorem. 12:40: But it was probably that Werner dude – he must have made some measurements and disentangled the particles en route. 11:45: ... measurements will be correlated in a way that depends on the choice of measurement basis at both ... 11:18: Our choice of measurement direction will set the diection of those spin or polarizations axes. 08:51: If someone... not Eve ... Werner, intercepted these messages, which were after all sent on a public channel, and did his own measurements. 09:37: Once they have done this test and verified that the information wasn’t intercepted, they discard the non-matching measurements and keep the rest. 11:45: ... in a different basis to its entangled partner, the results of the measurements will be correlated in a way that depends on the choice of measurement ... 12:23: Because they’re entangled, the outcome of Alberts and Niels measurements should be correlated in a very particular way defined by Bell’s theorem. 12:40: But it was probably that Werner dude – he must have made some measurements and disentangled the particles en route.
	2019-04-24: No Dark Matter = Proof of Dark Matter? 00:03: ... the orbits the Cosmic Microwave Background fluctuations also give us a measurement of the relative amount of dark matter in the early universe compared to ...
	2019-04-10: The Holographic Universe Explained 17:02: Measurements of the geometry of the universe indicate flatness, but we may never know whether it's truly flat, or just flat as far as we can see.
	2019-03-28: Could the Universe End by Tearing Apart Every Atom? 13:18: ... evidence that dark energy may be increasing in strength based on measurements of distant ...
	2019-03-20: Is Dark Energy Getting Stronger? 05:21: It may be an issue with how we determine the starting conditions of the universe, or it may be our measurements of supernovae. 05:38: But before we throw away the textbooks, perhaps we should think about where the measurements might have gone wrong. 05:44: ... surprisingly, our measurement of the state of the early universe via the CMB may be more reliable than ... 09:40: But if you make the measurement with enough quasars then this scatter can be averaged away. 13:17: But the most likely explanation is still that concordance, Lambda-CDM is right, and there’s an issue with the measurements or calculations. 13:36: ... there are still relatively few very distant quasars with good X-ray measurements, so maybe the random variations in the UV-to-X-ray ratio by chance to ... 05:21: It may be an issue with how we determine the starting conditions of the universe, or it may be our measurements of supernovae. 05:38: But before we throw away the textbooks, perhaps we should think about where the measurements might have gone wrong. 13:17: But the most likely explanation is still that concordance, Lambda-CDM is right, and there’s an issue with the measurements or calculations. 13:36: ... there are still relatively few very distant quasars with good X-ray measurements, so maybe the random variations in the UV-to-X-ray ratio by chance to ...
	2019-02-20: Secrets of the Cosmic Microwave Background 11:14: ... the first peak to measure the baryon content of the Universe And those measurements tell use that that baryons constitute only about 5% of the total energy ...
	2019-02-07: Sound Waves from the Beginning of Time 00:42: The impossibly vast distances made accurate measurements near impossible. 01:15: Today, we'll talk about another measurement that may help resolve this crisis: The baryon acoustic oscillations. 09:08: ... gives distance. And with careful measurements of galaxies' positions on the sky, a redshift survey can produce a ... 10:47: ... then, the WiggleZ BAOs and 6dF surveys have improved the measurements/ Now, there was a powerful driving motivation to make this measurement ... 11:00: Dark energy was first discovered by using distant supernovae as distance measurements- to track the rate of expansion of the universe. 00:42: The impossibly vast distances made accurate measurements near impossible. 09:08: ... gives distance. And with careful measurements of galaxies' positions on the sky, a redshift survey can produce a ... 10:47: ... then, the WiggleZ BAOs and 6dF surveys have improved the measurements/ Now, there was a powerful driving motivation to make this measurement ... 11:00: Dark energy was first discovered by using distant supernovae as distance measurements- to track the rate of expansion of the universe.
	2019-01-24: The Crisis in Cosmology 00:13: ...have refined its measurement to unprecedented precision. 00:49: Combined with the Doppler shift velocity measurements of Vesto Slipher,... 02:51: Historically, measurement of the Hubble constant... 04:15: ...and the precise measurement of the Hubble constant... 05:18: ...to refine our measurement of H0 to ever greater precision. 06:01: Well, in order to fully believe a measurement like this,... 06:12: So it's a more or less direct measurement of the CURRENT expansion rate. 06:37: ...or there is a big problem, with either our supernova measurements... 10:57: ...in either the supernova or Planck measurements. 12:26: The answer will depend on whether the more correct measurement of the Hubble constant... 14:03: ...the gravitational lensing measurements of dark matter... 00:49: Combined with the Doppler shift velocity measurements of Vesto Slipher,... 06:37: ...or there is a big problem, with either our supernova measurements... 10:57: ...in either the supernova or Planck measurements. 14:03: ...the gravitational lensing measurements of dark matter...
	2018-10-25: Will We Ever Find Alien Life? 15:05: ... with scientific method using accepted protocols of observation, measurement, and evaluation of ...
	2018-10-18: What are the Strings in String Theory? 00:59: We need to use physical measurement to fix 19 free parameters like the masses of particles.
	2018-10-03: How to Detect Extra Dimensions 01:50: Among other things, this optical identification gave a completely independent measurement of the distance traveled by the gravitational waves. 10:20: ... and the frequency of the wave combined with our independent distance measurement. ... 14:10: This only works if the number of measurements you need to make is finite. 14:14: For the simplest attempts at quantum gravity, you need infinite measurements. 14:10: This only works if the number of measurements you need to make is finite. 14:14: For the simplest attempts at quantum gravity, you need infinite measurements.
	2018-09-20: Quantum Gravity and the Hardest Problem in Physics 10:23: They can be brought back to reality by actual physical measurements of a few simple numbers in a process called renormalization. 10:31: ... example, measurement of the mass and charge of an electron renormalizes quantum ... 10:53: But unlike other quantum field theories, there are no simple measurements you can do to renormalize those corrections. 11:00: In fact, you would need infinite measurements to do so. 10:23: They can be brought back to reality by actual physical measurements of a few simple numbers in a process called renormalization. 10:53: But unlike other quantum field theories, there are no simple measurements you can do to renormalize those corrections. 11:00: In fact, you would need infinite measurements to do so.
	2018-08-15: Quantum Theory's Most Incredible Prediction 05:58: So measurements say the G factor is around 2. 11:38: This requires an independent experimental measurement. 05:58: So measurements say the G factor is around 2.
	2018-08-01: How Close To The Sun Can Humanity Get? 04:33: It'll make detailed measurements of their kinematic properties like velocity temperature and density.
	2018-07-25: Reversing Entropy with Maxwell's Demon 07:08: Weirdly, it's not in the measurement of particle trajectories or the motion of the door.
	2018-07-11: Quantum Invariance & The Origin of The Standard Model 02:49: The best we can do is make a measurement of physical observables, like position or momentum. 02:54: The wave function can represent different observables and it determines the distribution of possible results of measurement of those observables.
	2018-07-04: Will A New Neutrino Change The Standard Model? 09:35: This result is in conflict with some other measurements.
	2018-05-23: Why Quantum Information is Never Destroyed 08:06: After all, doesn't the act of measurement pick a single value of some quantity from the range of possible values? 08:35: And in principle, make enough measurements and you can extract all of the information from a wave function. 08:50: ... to that interpretation, the active measurement actually alters the entire wave function causing it to shrink down to ... 09:22: In the case of many-worlds, the entire wave function continues to exist even after measurement. 09:27: That measurement itself is just a thing that happens in one part of the possibility space. 08:06: After all, doesn't the act of measurement pick a single value of some quantity from the range of possible values? 08:35: And in principle, make enough measurements and you can extract all of the information from a wave function.
	2018-05-16: Noether's Theorem and The Symmetries of Reality 10:39: But Gaia is really optimized for extreme astrometry-- phenomenally accurate position data that actually allows measurements of velocities. 11:28: Simon Clarkston asks how Gaia can take such precise measurements. 10:39: But Gaia is really optimized for extreme astrometry-- phenomenally accurate position data that actually allows measurements of velocities. 11:28: Simon Clarkston asks how Gaia can take such precise measurements.
	2018-05-09: How Gaia Changed Astronomy Forever 02:07: Coupled with its incredible position measurements, this enables Gaia to measure distances to stars as far away as the galactic center. 05:07: ... putting such complete velocity measurements together with our position data, it's now possible to model the dynamics ... 06:27: ... by constraining the distances to stars, we can get better measurements on the sizes of those stars, and thus, also get better measures of the ... 08:10: It does this by providing better distance measurements to those pulsars. 02:07: Coupled with its incredible position measurements, this enables Gaia to measure distances to stars as far away as the galactic center. 05:07: ... putting such complete velocity measurements together with our position data, it's now possible to model the dynamics ... 06:27: ... by constraining the distances to stars, we can get better measurements on the sizes of those stars, and thus, also get better measures of the ... 08:10: It does this by providing better distance measurements to those pulsars.
	2018-03-28: The Andromeda-Milky Way Collision 03:01: Hubble went on to combine distance measurements to many galaxies with measurements of their velocities to discover the expansion of the universe. 03:32: But Doppler shift measurements only gives the line of sight velocity, the component of the galaxy's motion directly towards or away from us. 10:25: ... one thing, there's the consistency of the dark matter mass measurements of galaxies and galaxy clusters from gravitational lensing versus ... 03:01: Hubble went on to combine distance measurements to many galaxies with measurements of their velocities to discover the expansion of the universe. 03:32: But Doppler shift measurements only gives the line of sight velocity, the component of the galaxy's motion directly towards or away from us. 10:25: ... one thing, there's the consistency of the dark matter mass measurements of galaxies and galaxy clusters from gravitational lensing versus ...
	2017-12-06: Understanding the Uncertainty Principle with Quantum Fourier Series 01:59: And it's not just because our measurement of position requires us to interact with the particle, therefore changing its momentum, no. 08:12: ... how likely we are to find the particle at any given point when we make a measurement. ...
	2017-11-29: Citizen Science + Zero-Point Challenge Answer 02:32: This international database houses over 20 million variable star brightness measurements dating back over 100 years.
	2017-11-22: Suicide Space Robots 01:57: These measurements would have been impossible outside Venus' thick atmosphere. 08:58: ... 1 still sends faint radio signals, bringing us our first and only direct measurements from beyond our home ... 13:07: The paper claims the measurement of a real thrust. 01:57: These measurements would have been impossible outside Venus' thick atmosphere. 08:58: ... 1 still sends faint radio signals, bringing us our first and only direct measurements from beyond our home ...
	2017-11-08: Zero-Point Energy Demystified 01:26: This means we should take the idea of zero-point energy seriously and are justifiably perplexed at the mismatch between theory and measurements.
	2017-10-19: The Nature of Nothing 06:57: They live in the interval between measurements of real particles. 09:51: Neither the Casimir effect nor the Lamb shift allow measurement of the absolute strength of vacuum energy. 06:57: They live in the interval between measurements of real particles.
	2017-10-11: Absolute Cold 05:18: And this isn't about measurement.
	2017-09-28: Are the Fundamental Constants Changing? 04:18: ... first measurement of this fundamental parameter was through its effect on the fine grain ... 06:34: The key to this measurement is quasars. 08:26: ... challenge here is that the measurement is really, really difficult. Photons from these extremely distant ... 09:38: Well, any measurement of a change in Alpha may provide evidence to constrain the grand unified theories that predict such changes.
	2017-08-24: First Detection of Life 00:12: To detect life on a planet based on measurements by a space probe.
	2017-08-02: Dark Flow 05:02: A KSZ measurement from a single cluster isn't very useful. 11:34: Upon measurement of the properties of the outgoing particles, weed entanglement correlations can still occur. 11:41: ... the case of single entanglement, say, of two electrons, measurement of the properties of one of the electrons appears to influence the state ... 11:57: ... if that measurement instead happens after the electron undergoes an interaction, represented ...
	2017-07-12: Solving the Impossible in Quantum Field Theory 09:44: ... mass, and we know that because we've measured that mass, although any measurement we make actually includes some of this self-energy, so our measurements ... 10:05: ... you fold in a term for the self-energy corrected mass based on your measurement. ... 10:56: It can only make predictions of other properties relative to your lab measurements. 09:44: ... measurement we make actually includes some of this self-energy, so our measurements are never of the fundamental or bare mass of the electron, and that is ... 10:56: It can only make predictions of other properties relative to your lab measurements.
	2017-07-07: Feynman's Infinite Quantum Paths 00:00: ... properties, paths, or events that could reasonably occur between measurements do ...
	2017-05-03: Are We Living in an Ancestor Simulation? ft. Neil deGrasse Tyson 05:43: That's debatable, because the environment needs to be perfectly consistent with respect to all measurements made by all brains in that environment.
	2017-02-02: The Geometry of Causality 07:59: ... itself comes directly from the Lorentz transformation, as the only measurement of spacetime separation that is unchanging or invariant under that ...
	2017-01-11: The EM Drive: Fact or Fantasy? 01:23: ... Time Journal Club, we're jumping into Harold "Sonny" White, et al., 2016 "Measurement of Impulsive Thrust from a Closed Radio-Frequency Cavity in Vacuum." ... 03:24: The Eagle Works result is the latest in several attempts to reproduce Shawyer's measurements, none of which are close to being conclusive. 04:10: Twisting of the wire gives an extremely precise measurement of any force. 03:24: The Eagle Works result is the latest in several attempts to reproduce Shawyer's measurements, none of which are close to being conclusive.
	2016-11-30: Pilot Wave Theory and Quantum Realism 02:36: ... and Heisenberg insisted that in the absence of measurement, the unobserved universe is only a suite of possibilities of the various ... 05:01: Apparent randomness arises because we can't ever have a perfect measurement of initial position, velocity, or other properties. 09:25: So a measurement at one point in the wave function will affect its shape elsewhere. 02:36: ... states it could take were a measurement to be made, and that upon measurement fundamental randomness determines the properties of, say, the particle that would ...
	2016-11-09: Did Dark Energy Just Disappear? 07:28: Those blue ovals represent the ranges of combinations of matter and dark energy that are consistent with the new supernova measurements. 10:20: The 1, 2, and 3-sigma contours based on the CMB measurements. 10:33: When you mathematically combine the certainty contours of two completely independent measurements they give you a much tighter range of possibilities. 07:28: Those blue ovals represent the ranges of combinations of matter and dark energy that are consistent with the new supernova measurements. 10:20: The 1, 2, and 3-sigma contours based on the CMB measurements. 10:33: When you mathematically combine the certainty contours of two completely independent measurements they give you a much tighter range of possibilities.
	2016-10-26: The Many Worlds of the Quantum Multiverse 01:45: And those many maybe histories somehow interact with each other to determine the most likely final destination when a measurement is made. 02:04: ... the original Copenhagen interpretation of quantum mechanics, the act of measurement was thought to collapse possibility space into a single reality, at ... 03:55: ... the double-slit experiment and spookily correlated quantum entanglement measurements. ...
	2016-09-29: Life on Europa? 09:45: ... you would get if you measured one particle with a vertically-aligned measurement device and a second particle with a horizontally-aligned ... 09:57: ... mechanics is if you measure the spins of both particles with the same measurement ... 10:17: ... spins in the same direction, depending on the relationship of the chosen measurement axis with the hidden spins of the ... 10:42: That's because the measurement of its entangled twin forces its alignment to be 90 degrees to its own measurement axis. 11:37: ... way of saying that is that this measurement interaction effectively entangles the measured particle and its partner ... 12:47: ... no need for a faster-than-light signal to tell particle a what measurement has been carried out on particle B because the universe, including ... 09:57: ... mechanics is if you measure the spins of both particles with the same measurement axis. ... 10:17: ... spins in the same direction, depending on the relationship of the chosen measurement axis with the hidden spins of the ... 10:42: That's because the measurement of its entangled twin forces its alignment to be 90 degrees to its own measurement axis. 09:45: ... you would get if you measured one particle with a vertically-aligned measurement device and a second particle with a horizontally-aligned ... 11:37: ... way of saying that is that this measurement interaction effectively entangles the measured particle and its partner with a ...
	2016-09-21: Quantum Entanglement and the Great Bohr-Einstein Debate 01:48: ... the intervals between measurement, quantum systems truly exist as a fuzzy mixture of all possible ... 02:08: And our experience of a well-defined material universe only has meaning at the moment of measurement. 03:49: ... according to the Copenhagen interpretation, any measurement of one particle automatically collapses the entire entangled wave ... 05:04: Measurement of the spin of one of these particles tells us the spin of the other, no matter how large the distance between them. 05:10: But in quantum mechanics, measurement actually affects the thing you are measuring. 05:15: In the case of quantum spin, that measurement effect is especially weird. 05:31: We always find that the observed quantum spin aligns itself with our chosen measurement axis. 05:48: Measurement forces the alignment of the measured particle. 06:00: ... was right, imagine the response of each particle to all possible spin measurements is encoded in each particle at the moment of their creation as hidden ... 06:28: But there'll be no correlation due to our choice of measurement axis. 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. 06:59: That should lead to a correlation between our choice of measurement axis for the first particle and the spin direction then measured for the second. 08:11: ... found that there was a correlation between the choice of polarization measurement axis for one photon and the final polarization direction of its ... 10:04: ... only possible to see the influence between the entangled partners after measurements have been made and those measurements are compared, just as we saw with ... 05:31: We always find that the observed quantum spin aligns itself with our chosen measurement axis. 06:28: But there'll be no correlation due to our choice of measurement axis. 06:59: That should lead to a correlation between our choice of measurement axis for the first particle and the spin direction then measured for the second. 08:11: ... found that there was a correlation between the choice of polarization measurement axis for one photon and the final polarization direction of its entanglement ... 05:15: In the case of quantum spin, that measurement effect is especially weird. 05:48: Measurement forces the alignment of the measured particle. 01:48: ... the intervals between measurement, quantum systems truly exist as a fuzzy mixture of all possible properties-- what ... 03:49: ... the entire entangled wave function, and so affects the results of measurements of the other ... 06:00: ... was right, imagine the response of each particle to all possible spin measurements is encoded in each particle at the moment of their creation as hidden ... 10:04: ... only possible to see the influence between the entangled partners after measurements have been made and those measurements are compared, just as we saw with ...
	2016-08-10: How the Quantum Eraser Rewrites the Past 03:26: It's impossible to make these measurements without messing up the wave.
	2016-06-15: The Strange Universe of Gravitational Lensing 05:57: ... distance measurements have allowed us to measure the Hubble Constant, which tells us the rate ...
	2016-06-01: Is Quantum Tunneling Faster than Light? 07:39: At that point, you can get an incredibly precise measurement of any differences in photon travel time.
	2016-05-18: Anti-gravity and the True Nature of Dark Energy 00:56: Paradoxically, our measurements points a near-perfect flatness.
	2016-05-04: Will Starshot's Insterstellar Journey Succeed? 11:49: There's a whole sequence of steps we use to calibrate astronomical distance measurements.
	2016-04-27: What Does Dark Energy Really Do? 09:19: That's what we see in our white dwarf supernova measurements.
	2016-04-20: Why the Universe Needs Dark Energy 01:41: There are two powerful and completely independent measurements that can test this prediction of the fate of the universe. 01:48: Today, let's look at one of these measurements-- the geometry of the universe, which points to a discrepancy in the first Friedmann equation. 06:21: So, did we miss up our measurements? 01:41: There are two powerful and completely independent measurements that can test this prediction of the fate of the universe. 01:48: Today, let's look at one of these measurements-- the geometry of the universe, which points to a discrepancy in the first Friedmann equation. 06:21: So, did we miss up our measurements?
	2016-03-30: Pulsar Starquakes Make Fast Radio Bursts? + Challenge Winners! 00:59: And that distance measurement allowed scientists to calculate the FRB power output as that of 500 million Suns.
	2016-03-23: How Cosmic Inflation Flattened the Universe 02:57: Based on the precision of our measurements so far, we know that the curvature is within 0.4 of 1% of perfect flatness.
	2016-02-03: Will Mars or Venus Kill You First? 09:28: The universe is 13.8 billion years old here, and that measurement of age is really just a measurement of how much change has happened in our frame.
	2015-12-16: The Higgs Mechanism Explained 03:00: ... only way that we know that the tiny neutrino has mass, and it was the measurement of those neutrino oscillations the won the 2015 Nobel Prize in ...
	2015-10-22: Have Gravitational Waves Been Discovered?!? 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 12:04: ... you collapse the way function of one entangled particle, your choice of measurement affects the state of its entangled partner instantaneously, potentially ...
	2015-10-07: The Speed of Light is NOT About Light 11:26: ... curvature is the maximum that it could be, given the current flatness measurements. ...
	2015-09-30: What Happens At The Edge Of The Universe? 03:37: Given our best measurements of cosmological parameters, we think that the cosmic event horizon is around 16 billion light years away. 05:18: Measurements of the distribution of galaxies and the CMB confirm this flatness with very high, but not infinite, precision. 06:21: It's very possible that the universe has curvature just inside the uncertainty range of the best measurements to date. 03:37: Given our best measurements of cosmological parameters, we think that the cosmic event horizon is around 16 billion light years away. 05:18: Measurements of the distribution of galaxies and the CMB confirm this flatness with very high, but not infinite, precision. 06:21: It's very possible that the universe has curvature just inside the uncertainty range of the best measurements to date.
	2015-04-22: Are Space and Time An Illusion? 05:08: In contrast, our experiences and measurements of time and space don't correspond to anything, per se.
	2015-04-08: Could You Fart Your Way to the Moon? 05:50: And if anyone is aware of documentable measurements of flatological exhaust speeds, include those too.
	2015-04-01: Is the Moon in Majora’s Mask a Black Hole? 01:19: Both analyses are extremely well done, and I'm actually going to rely on MatPat's measurements in this episode. 03:45: I've worked out the algebra using that MatPat's measurement of a mere 30-ish meters for the radius of Termina's moon. 01:19: Both analyses are extremely well done, and I'm actually going to rely on MatPat's measurements in this episode.
	2015-03-18: Can A Starfox Barrel Roll Work In Space? 05:42: ... what a space meter is, which is apparently the official unit of measurement in the "Star Fox" ...
	2015-03-11: What Will Destroy Planet Earth? 05:37: And those measurements, while not conclusive, do allow for a scenario that physicists call The Big Rip.
	2015-02-11: What Planet Is Super Mario World? 02:55: ... turns out, other people have done more sophisticated versions of these measurements using Nintendo emulators, screen capture programs, and actual ... 05:38: Remember, you could try this experiment yourself, even with rough measurements like mine. 05:47: ... any actual planet, please let me know in the comments, along with your measurements. ... 02:55: ... turns out, other people have done more sophisticated versions of these measurements using Nintendo emulators, screen capture programs, and actual ... 05:38: Remember, you could try this experiment yourself, even with rough measurements like mine. 05:47: ... any actual planet, please let me know in the comments, along with your measurements. ...

114 result(s) shown.

Help · About · Index