
20221208: How Are Quasiparticles Different From Particles?
 00:03: ... this video on is best understood by thinking about positive and negative charges moving around a circuit of diodes and ...
 00:12: But the only elementary particle actually flowing in the circuit are the negatively charged electrons.
 00:19: And yet those flowing positive charges are there, in the form of a particle you may never have heard of.
 02:25: It has an effective positive charge due to the charge of the nucleus not being properly canceled by electrons in that location.
 03:21: This is an ntype semiconductor  n because the flowing charge is negative.
 03:32: ... gaps in the underfilled valence shells  so we have flowing positively charged electron holes and a ptype ...
 03:48: ... ptype so we end up with a region where all valence shells are filled so charge can’t ...
 10:50: At the same time, the negatively charged electrons in a metal lattice attract the positive nuclei.
 10:57: ... direction of a freemoving electron, and that tiny increase in positive charge can in turn attract more ...
 11:26: ... electrons that were attracted by this momentary convergence of positive charge are jostled so much that this effect is tiny But if the metal is really, ...


20221123: How To See Black Holes By Catching Neutrinos
 01:32: ... neutrinos are electrically neutral and have much lower masses than the charged ...
 03:50: ... will continue through the ice, emitting light as it interacts with other charged ...
 04:32: ... expanding EM waves created by the charged particle expand slower than the particle itself, so their wavefronts ...


20221116: Are there Undiscovered Elements Beyond The Periodic Table?
 06:40: ... the electromagnetic force trying to force apart all those positively charged protons, and the strength of that force is great due to the proximity of ...
 07:36: However, electromagnetism just keeps getting stronger the closer two electric charges get.


20221019: The Equation That Explains (Nearly) Everything!
 07:51: ... several times depending on the dimensions of spacetime, the number of charges, the number of different particles, or things like that Next we do ...
 10:36: ... each field is preceded by a new symbol which represents the charge that field interacts with: electric charge, isospin, hypercharge, and ...


20221012: The REAL Possibility of Mapping Alien Planets!
 19:23: ... Well yes! The fine structure constant is defined as the electron charge squared divided by 4pi time the vacuum permittivity the ...


20220928: Why Is 1/137 One of the Greatest Unsolved Problems In Physics?
 02:55: ... was always a multiple of one particular number: the square of the charge of the electron, divided by four times pi, the permittivity of free ...
 03:28: ... charge of the electron is in Couloumbs, the speed of light in meters per ...
 05:34: Those probabilities depend on many things, like the particles’ positions and momenta, spins, charges, masses, etc.
 10:02: There’s no way for the alien civilization to recognize these numbers without knowing our units for distance, time, mass, electric charge, etc.
 13:07: Or perhaps it hints at a deeper connection between the properties of the elementary particles, like the mass and charge of the electron.


20220914: Could the Higgs Boson Lead Us to Dark Matter?
 05:46: ... particles with electrical charge OR color charge can’t decay into Higgs bosons, because the Higgs itself ...
 06:01: ... that excludes the electrically charged leptons: electrons, muons and tau particles; it excludes the quarks and ...


20220824: What Makes The Strong Force Strong?
 00:28: ... are held in their orbitals by the electromagnetic force  opposite charges attract, so the negativelycharged electrons are attracted by the ...
 00:39: But in electromagnetism, like charges repel.
 02:03: ... you arrange particles according to their strangeness and their electric charge, they fall into geometric patterns like this hexagon with eight particles ...
 04:31: With electromagnetism you have one type of charge, which can be positive or negative, with the Strong Force you have three charge types.
 04:45: In fact we label these three strong force charges with the colours red, green and blue.
 05:07: If we have different charges then we have a potential for attractive forces.
 06:03: Electrically charged particles interact with each other via the electromagnetic field.
 06:07: We can think of each charged particle as generating a constant buzz of virtual photons around it, forming what we think of as its EM field.
 08:26: It ensures that color charge is mostly only felt inside the hadrons.
 08:49: Let's say we have a proton and an electron, their electric charges attract and they form a neutral hydrogen atom.
 08:55: ... is what electrical charges do, they attract each other until their electric fields cancel out, ...
 09:13: Something similar happens with color charges.
 09:20: This makes sense when we have two quarks, they have opposite color charges so they cancel out.
 09:46: In fact each color charge is equal to having the opposite of the other two.
 10:28: ... to be the same as the mathematics that describe the behavior of the charges of the strong ...
 10:37: ... has 3 primary colors like the 3 charges of the strong force, each of which can be positive or negative, and ...
 10:50: This apparent coincidence is why physicists called them color charges in the first place.
 11:32: That means photons can interact with objects without affecting their electric charge, and thus neutral objects can interact with magnetic fields.
 11:51: ... carry color charge, in fact they carry two charges at the same time  a positive and a ...
 13:14: Six of them have color charge, and two of them are neutral but unbalanced.
 13:40: The position of each object in the hexagon tells you how much they have of a certain kind of quark, a certain color charge, or actual color.
 14:57: By chance we have the same number as their are degrees of freedom in the strong force colour charge.


20220803: What Happens Inside a Proton?
 01:31: ... describes the interactions of electrons and any other charged particle via photons. We’re going to come back to a ...
 02:06: ... of the one type of charge in QED, in QCD there are three  which we call colour ...


20220720: What If We Live in a Superdeterministic Universe?
 16:03: Agnibho Dutta asks if there’s any symmetry in physics, which holds for transformations in the color charge?
 16:12: Actually yes, they do decay exactly the same way besides influencing the color charge of their decay products.
 17:03: ... that note, Dandelion Stitches points out that the problem with electric charge sign convention could be resolved by including a list of common ...
 17:13: If the aliens simply describe the hydrogen atom and we saw that its electron had positive charge, we’d be set.


20220630: Could We Decode Alien Physics?
 00:00: ... from each other by their relative masses, color charge, etc. The particle running through the alien circuitry ...
 01:25: ... not electronic. It’s just that they define electric charge in the opposite way  electrons positive, positrons ...
 02:25: ... that out, let’s recall how we humans decided on our own electric charge sign convention. It was a pretty arbitrary choice ...
 04:59: ... equations tell us how particles with electric charges respond to each other. They don’t care what names we give those ...
 05:20: ... of physics to determine the alien sign convention for electric charge. ...
 05:33: ... seem to be identical except for having exactly opposite charges. The universe is mostly symmetric under charge conjugation  ...
 06:55: ... there yet. The Franklin convention for the sign of electrically charged particles is not the only arbitrary choice we’ve made in our ...
 07:38: ... using something called the cross product. Force equals charge times velocity cross magnetic field. This is a type of vector ...
 10:41: ... our universe Psymmetry is broken in much more obvious ways than charge symmetry. That’s because the Weak Force only ...
 11:52: ... symmetric. But if time reversal is equivalent to chargeparity inversion, and the latter is a broken symmetry, then time ...
 16:39: ... Well actually a magnetic shield may be enough to block many charged particles, but neutral particles like dust would pass ...


20220622: Is Interstellar Travel Impossible?
 18:50: ... can be observed about a black hole from its exterior are mass, spin, and charge. ...


20220504: Space DOES NOT Expand Everywhere
 13:50: ... our hair out writing this episode, gave the correct answer: when a charged particle is created in a particle collider it travels through the ...


20220427: How the Higgs Mechanism Give Things Mass
 01:11: The W bosons are especially weird in that they also have electric charge.
 04:37: ... look like weak isospin and weak hypercharge, but no electric charge. In our universe these three quantities are sort of ...
 05:24: ... are tightly coupled, and their combination defines electric charge. Is it time to give up on this symmetry stuff ...


20220420: Does the Universe Create Itself?
 00:59: ... is a phenomenon, until it is an observed phenomenon”. Bohr led the charge with this observerdependent view, encapsulated in his Copenhagen ...


20220323: Where Is The Center of The Universe?
 14:46: ... of habitable worlds, and the other one where we asked whether electric charge really is a fundamental property of ...


20220316: What If Charge is NOT Fundamental?
 00:00: If you've studied any physics you know that like charges repel and opposite charges attract.
 00:07: It's as though this thing  electric charge  is as fundamental a property of an object as its mass.
 00:14: Well it turns out if you dig deep enough, the fundamentalness of charge unravels, and in many things, including mass itself, unravel with it.
 00:44: Except that all of electromagnetism is powered by a single property: electric charge.
 00:50: And neither Maxwell’s equations nor QED say a thing about what electric charge really is.
 01:20: But actually, in the case of electric charge we have at least one or two more “but why’s” with which we can annoy the universe.
 01:52: ... with the only major difference being our mysterious friend  electric charge. ...
 02:06: The neutron seemed like a chargeless, or neutral proton, hence the name.
 03:44: But for isospin to really do its job, it needed to explain the most obvious difference between protons and neutrons  which is to say electric charge.
 03:53: Charge would have to depend on isospin, which could mean that charge is not a fundamental property after all.
 04:14: For example, some of these particles had very similar masses but very different electric charges, which I hope reminds you of the proton and neutron.
 04:33: But what exactly was the connection between isospin and electric charge?
 04:54: Similar to how the electron and positron are only created in pairs in order to conserve electric charge.
 05:00: But these new particles weren’t doing this to conserve charge, nor isospin, nor any other known property.
 05:13: ... this new property seemed to obey the math for our old friend electric charge. ...
 05:30: Electric charge, isospin and hypercharge were intimately connected across all particles.
 05:37: In fact, it seemed that electric charge was just isospin plus half of hypercharge.
 05:57: Charge alone couldn’t explain the patterns of interactions and particle types observed in the particle zoo.
 06:04: However hypercharge and isospin seemed to do a much better job  suggesting that these may in fact be more fundamental than charge.
 07:05: Isospin and hypercharge seemed to be “deeper” than electric charge.
 08:12: So after all this hard thinking it turns out that isospin and hypercharge were as much mathematical abstractions as was electric charge.
 08:21: ... differences between particle groups, and that also governs electric charge. ...
 08:59: ... by unraveling one of the forces of nature that we can explain electric charge  but it's not the strong force, it's not even ...
 09:07: The secrets of electric charge are actually hiding in the last, most obscure of the quantum forces  the weak force.
 10:45: Weak isospin is effectively the charge of the weak force, carried by these W bosons.
 10:52: To fully explain weak interactions we need a second charge  this one carried by the Z boson.
 10:58: It acts more like electric charge, so we'll be imaginative and call it weak hypercharge.
 11:14: Which is to say, electric charge equals weak isospin plus half weak hypercharge.
 11:35: That's right, quarks feel the weak force and obey the same rule for their electric charge.
 11:55: Let me summarize where we've got to: the charge that drives electromagnetism is governed by the charges that drive the weak force.
 12:04: So does that mean that electric charge is not really fundamental?
 12:20: ... two forces were once united in what we call the electroweak force, whose charges were the same weak isospin and hypercharge that we just ...
 12:31: ... happened to that force in the very early universe to force these charges to only take on a specific combination of values  the combination that ...
 12:50: So we now know that electric charge is a sort of shadow of the ancient fields from the birth of the universe.
 13:15: But is it any more fundamental that the dubiously fundamental electric charge?


20220216: Is The Wave Function The Building Block of Reality?
 11:09: ... other collapsing field. If the quantum object happens to be electrically charged, then the constant jiggling and acceleration caused by this Brownian ...


20220127: How Does Gravity Escape A Black Hole?
 06:16: ... example the electromagnetic force is communicated between charged particles by transferring virtual photons  ephemeral excitations in the ...
 10:30: And this last argument also tells us how it can be that a black hole can possess electric charge.
 10:37: If a black hole swallows electric charge, the electromagnetic field around the black hole grows.
 10:45: Because when you look at a charged black hole you still have causal contact with all the charge that fell into it.
 10:51: You interact with the past charge, not the present.
 10:55: ... the point of view of that charge, it’s inside the black hole, but from your point of view it’s frozen on ...


20220112: How To Simulate The Universe With DFT
 10:11: ... position density  or more commonly the charge density  is just a tiny fragment of the information held in the total ...
 10:29: ... HohenbergKohn theorems say that you can map from this charge density to the interesting observables  like the energy of the system, ...
 10:42: ... we start with a bad guess at the ground state charge distribution and then iterate closer to the truth, and we do this for ...
 11:23: Solving those equations becomes possible, and it gets you the ground state energy for your guess at the charge density.
 11:30: Then iterate until everything is consistent  when the ground state energy, the potential, and the charge density converge.
 11:37: ... according to the theorem that we started with, that ground state charge distribution is unique  it corresponds both to the fake noninteracting ...


20211210: 2021 End of Year AMA!
 00:02: ... places the space telescope science institute which back then was in charge of operating the still quite shiny hubble space telescope did that for ...


20211117: Are Black Holes Actually Fuzzballs?
 01:14: ... that we can observe from outside a black hole are its mass, electric charge, and angular ...
 02:56: The nohair theorem says that there’s no information beyond charge, mass and spin that’s observable above the event horizon.


20211013: New Results in Quantum Tunneling vs. The Speed of Light
 15:57: Same as if the black hole held electric charge; it would produce an electric field.
 16:01: And presumably if black holes had enormousmagnetic charges we’d see that in the way they interact with matter.


20211005: Why Magnetic Monopoles SHOULD Exist
 00:35: ... cut the bar in half and you get a pair of electric charges  one negative and one positive, both of which have electric fields that ...
 00:55: So if we cut this bar in half surely we get a pair of magnetic charges similar to our electric charges, right?
 01:11: ... matter how many times you slice it  you’ll never get isolated magnetic charges  what we call magnetic ...
 01:51: ... spin or or a circular electric current there’s a sense of electric charge in ...
 02:06: And according to classical electrodynamics, moving electric charge is the source of the magnetic field.
 02:12: If that’s true then, why should we even expect there to be isolated magnetic charges  magnetic monopoles?
 03:00: ... of the electric field is not zero  it’s equal to the electric charge ...
 03:09: That charge density is where the electric field lines can end  it forms their source or their sink.
 03:16: So there are such things as isolated electric charges.
 03:23: This is them without any charges  electric or magnetic.
 03:30: ... and magnetism which only gets screwed up when you put in the electric charge  here in the form of charge density and current ...
 03:40: You could also have symmetry between these equations if there was such a thing as magnetic charge.
 03:46: If you add magnetic charges to these equations then you get a magnetic force that looks exactly like the electrostatic force.
 04:05: ... exist except for the fact that James Clark Maxwell set the magnetic charge to zero because he didn’t believe it ...
 04:26: ... electromagnetism by explaining it in terms of quantum fields rather than charges and ...
 05:09: ... divergence  its field lines can never end  so it can’t have its own charge, unlike the electric ...
 06:23: So make the width of the coil much smaller than the length, and it looks like two isolated magnetic charges.
 06:49: So magnetic fields affect charged particles.
 06:57: Imagine a charged particle  say an electron  passing by a Dirac string.
 07:29: The amount of the phase shift is proportional to the electric charge.
 07:34: ... the right value of that charge, the phase shift induced between the different sides of the string is ...
 07:42: ... for the Dirac string to be undetectable then electric charge can only exist in integer multiples of that basic charge This is a very ...
 08:13: ... one hand this was taken as a prediction of the quantization of electric charge  electric charge has to be discrete if there’s even a single magnetic ...
 08:25: And of course we know that electric charge really is quantized  it can only be integer multiples of the charge of the electron.
 08:31: Or maybe of quarks  a third the electron charge.
 08:34: ... instead of taking this as a prediction of charge quantization, you can also flip it: magnetic monopoles are possible if ...
 08:45: Charge turns out to be quantized, so quantum mechanics doesn’t actually forbid monopoles.
 10:55: And it turns out these knots in the Higgs field in GUT theories behave as massive particles with magnetic charge  magnetic monopoles.
 12:48: ... lab and managed to detect what looked like a monopole with the same charge predicted by Paul ...
 14:18: Kyle, we are taught by Paul Dirac that if there's even a single magnetic monopole in the entire universe then electric charge must be quantized.
 14:36: ... Kyle  is doubly important  sure, it ensures the quantization of all charge, but it also serves as a testament to the generosity of ...
 15:39: ... his book “what is spin?” showed that spin can be described as a circular charge current in the Dirac ...


20210915: Neutron Stars: The Most Extreme Objects in the Universe
 02:00: ... currents flowing the other way due to their opposite electric charges. These and other charged particles end up being ...
 04:39: ... how nuclei can bind to each other given that they’re all positively charged and so should repel. Well, at these densities nuclei ...
 05:48: ... iron nuclei in a process called electron capture. The negatively charged electrons merge with positively charged protons to ...


20210907: First Detection of Light from Behind a Black Hole
 01:13: We talked about this soon after it came out  but to remind you, here we have radio light from charged particles whirling around the black hole.


20210810: How to Communicate Across the Quantum Multiverse
 09:57: ... magnets  a north and south pole  that deflect particles with spin and charge. It measures the direction of spin by whether the particles are deflected ...


20210803: How An Extreme New Star Could Change All Cosmology
 09:51: ... stars and planets are generated by dynamos  selfsustaining currents of charged particles. A collision like this could well produce the sort of ...


20210721: How Magnetism Shapes The Universe
 01:29: The nuclear forces are short range, and the electrostatic force never adds up to much because its positive and negative charges tend to cancel it out.
 01:39: It’s generated when electrically charged particles move.
 01:43: Even if the substance is electrically neutral you’ll still get a magnetic field as long as the charges are moving in opposite directions.
 02:12: Magnetic field lines form in concentric circles around moving charges.
 02:16: ... that charge moves in a loop, that results in a dipole field  sort of a torus around ...
 02:30: ... a moving charged particle will feel a force perpendicular to both its direction of motion ...
 02:43: ... if that charge already has a circular motion  for example the electric current in an ...
 04:21: We can see those tangled field lines in ultraviolet light as charged particles spiral along them, up and down from the Sun’s surface.
 08:30: These are the densest regions of those galactic disks  places where magnetic fields have confined the charged particles of the interstellar plasma.
 14:24: Moving charges exert forces on other moving charges  that’s what it always comes down to with magnetism.
 14:30: In ferromagnets, the “moving” charges are the electron spins.


20210707: Electrons DO NOT Spin
 01:26: ...  it’s a quantum property of particles, like mass or the various charges. But it doesn’t just cause magnets to move in funny ways  it turns out ...
 02:25: ... the ideas of classical physics. If you think of an electron as a ball of charge moving in circles around the atom, that motion leads to a magnetic ...
 03:48: ... to make sense, we really need to think of electrons as balls of spinning charge  but that has huge problems. For example, in order to produce the ...
 11:34: ... spin angular momentum and magnetic moment by looking at the energy and charge currents in the so called Dirac ...


20210407: Why the Muon g2 Results Are So Exciting!
 01:56: ... part of the Standard Model that describes how particles with electric charge interact via the electromagnetic force, quantum ...
 02:05: One of the interactions that QED describes is how a charge particle will tend to rotate to align with a magnetic field.
 03:09: Every particle with electric charge also has quantum spin.
 03:15: ... spin do generate a magnetic field, same as if you send an electric charge around a looped wire, or have electrical currency in Earth's spinning ...
 03:43: For a rotating charge, that depends on the objects rate of rotation, or angular momentum, it's charge and it's mass.
 03:50: Here's the equation for the classical dipole moment for a nonquantum rotating charge.
 04:00: An electron also has a dipole field and a dipole moment which depends on the electron spin charge and mass.
 04:15: So the electron responds to a magnetic field twice as strongly compared to what you'd expect for an equivalent classical rotating charge.
 04:33: In this theory, electromagnetic interactions result from charge particles communicating by exchanging virtual photons.
 07:23: They have the same exact charge, interact with the same forces, and have the same quantum spin.


20210309: How Does Gravity Affect Light?
 03:56: ... that generates a photon can be thought of as a clock  be it an electric charge pulsing up and down a radio antenna, or an atom vibrating back and forth ...


20210126: Is Dark Matter Made of Particles?
 02:05: Any electrically charged particle experiences the electromagnetic force and can communicate with other charged particles by exchanging photons.
 03:27: ... matter can’t have charge but it must have mass because the only thing we’ve ever actually seen ...


20201222: Navigating with Quantum Entanglement
 02:52: ... in their beaks which help them orient; others have proposed electrically charged fluids sloshing around in the inner ...
 04:56: Magnetic fields exert a force on a moving or rotating charged particle.
 05:00: An electron, for example, can be thought of as a spinning charge, and magnetic fields can cause that spin to flip direction.


20201104: Electroweak Theory and the Origin of the Fundamental Forces
 02:19: But Fermi’s model only worked at low energies, and neither it nor its successors explain why the weak interaction violates chargeparity symmetry.
 02:36: ... effort was quantum electrodynamics, in which charged particles interact not by actually touching  but via a mediating ...
 03:12: Given that the weak interaction could change a neutral particle into a pair of charged particles this mediating particle must itself be charged.
 03:20: This was an early hint that somehow the electromagnetic force, which acts on charged particles, was playing a role here.


20200824: Can Future Colliders Break the Standard Model?
 01:22: ... or linac, which uses oscillating electric fields to accelerate charged particles in a straight line, while the beam is focused by magnetic ...


20200817: How Stars Destroy Each Other
 04:38: ... charged particles spiral along the magnetic field lines they emit synchrotron ...


20200728: What is a Theory of Everything: Livestream
 00:00: ... you would call those the lepton number the spin and the char electric charge and so on but that's just the words that we humans made up right the ...


20200720: The Boundary Between Black Holes & Neutron Stars
 12:18: ... about how to dissolve a black hole event horizon by adding rotation or charge to the black hole, and also about experiments at CERN to study the ...
 12:34: ... trying to disolve an event horizon by throwoing more and more electric charge into it  Ultimantis points out that it would be increasingly difficult ...


20200708: Does Antimatter Explain Why There's Something Rather Than Nothing?
 00:22: ... an antiparticle identical in every way, but with the opposite charge and spin. An electron has a positron; a proton, an antiproton; and so ...
 02:12: ... or all of them, and the laws of physics should be unchanged. We have charge conjugation, where positive and negative charges are swapped; we have ...
 03:13: ... image of our universe would be distinguishable from our own. Then, charge and parity combined, or CP, also fell, with the observation of the ...
 05:19: ... have the exact same properties as its matter counterpart, besides the charge and spin thing — it must have the same mass, the same quantum energy ...
 09:19: ... states is determined by many different factors: the precise mass and charge of the particles, their orbital angular momentum, their magnetic and ...


20200630: Dissolving an Event Horizon
 02:22: According to the socalled nohair theorem, black holes can have only three properties  mass, electric charge, and spin.
 04:02: There’s a similar situation with the charged black hole  which, absent rotation, is described by the ReisnerNordstrom metric.
 04:10: ... presence of electric charge at the central singularity  which pointlike in this case  results in ...
 04:28: The more electric charge you drop into a black hole, the larger its inner horizon becomes.
 04:43: ... an extremal black hole  a black hole with the maximum amount of spin or charge while still having an event ...
 04:57: In both cases, the amount of angular momentum or charge you can fit into a black hole before it becomes extremal depends on the mass.
 05:07: More mass means more inward gravity, and so the black hole can hold more spin and charge before going extremal.
 05:20: Just add enough spin or charge to an existing black hole.
 05:24: And actually there’s another way to do it in the case of the charged black hole.
 05:52: So that means a massive CHARGED black hole will slowly leak away its mass while retaining its charge.
 06:31: ... the universe decay, we may be left with only radiation and these naked, charged ...
 06:52: So why shouldn’t it be possible to add a little more spin or charge to produce true naked singularities?
 09:09: For charged black holes the situation is in some ways easier, but has its own weirdness.
 09:23: A charged black hole in the vicinity of any matter would repel like charges and attract and swallow opposite charges, and so quickly neutralize.
 09:32: But imagine we create a charged black hole and isolate it from all other matter.
 09:37: Then surely we can just throw charged particles into the black hole.
 09:41: ... those particles increase the mass of the black hole as well as the charge  and if the mass increases too much it won’t go ...
 09:51: ... electrons have very tiny masses for comparatively large charge  just factoring the electrons mass, it should be easy to send a black ...


20200518: Mapping the Multiverse
 01:16: ... that mass is NOT rotating and does not have any electric charge, the result is a Schwarzschild black hole, which is about as simple as ...
 01:28: Add a little spin or charge and things get even weirder.
 01:33: Now, we’re going to focus on rotating black holes here, but a lot of this also applies to charged black holes, as we’ll see.
 01:53: We sometimes call a rotating black hole with no electric charge a Kerr black hole.
 12:58: This whole counterstreaming instability thing was figured out by Roger Penrose in the context of charged, nonrotating black holes.
 13:13: ... electrically charged, or ReissnerNordström black holes the electromagnetic field within ...


20200428: Space Time Livestream: Ask Matt Anything
 00:00: ... in mass when they swallow things they conserve angular momentum and charge because they acquire those properties when they swallow things those ...


20200422: Will Wormholes Allow Fast Interstellar Travel?
 01:09: ... thread the funnels with electromagnetic field lines then they act like charged ...
 11:48: ... not need exotic matter  and that’s the wormhole through a rotating or charged black hole. Now I’ve promised a more indepth episode on rotating black ...


20200324: How Black Holes Spin Space Time
 01:35: According to the nohair theorem, black holes can have three and only three properties: mass, electric charge, and spin.
 01:44: ... black holes in the first place. Essentially no black holes have electric charge  if somehow one does acquire charge it would quickly lose it because it ...
 02:36: ... and describing the Kerr black hole, which has mass and rotation but no charge. ...
 10:51: ... spins up the magnetic field into a gigantic particle accelerator. Charged particles are accelerated along those magnetic field and can radiate ...


20200211: Are Axions Dark Matter?
 01:05: ... flip the sign of the x, y, and z axes. Another example is flipping the charges of particles  positive to negative and vice versa  most of the ...
 03:02: ... an electric field like you’d get from a pair of positive and negative charges  an electric dipole field. Our very sensitive measurements have found ...
 06:54: ... quite well. This hypothetical axion particle would have no electric charge, no quantum spin, be extreme ly light  a tiny fraction of the mass of ...
 07:53: ... such an elusive particles? Well, even though axions have no electric charge, they can still interact with the electromagnetic field and produce ...


20200203: Are there Infinite Versions of You?
 07:55: ... things like the mass or charge or other properties of individual particles, an infinite range means ...


20200106: How To Detect a Neutrino
 01:37: ♪ ♪ ♪ ♪ Neutrinos also come in three flavors: ♪ ♪ one for each of the charged leptons.
 02:58: ♪ ♪ That's possible because, unlike neutrinos, protons have an electric charge.
 03:09: ♪ ♪ More magnetic fields are used to sort the positively charged pion particles from the debris ♪ ♪ and focus *them* into a beam.
 05:37: ... interacts in our detector, ♪ ♪ an Argon nucleus is broken apart and charged particles are released  in particular, pions and ...
 05:52: ♪ ♪ We charge the sides of the detector, so a giant electric field fills the entire tank.


20191007: Black Hole Harmonics
 09:44: General relativity predicts that black holes should be completely defined by three properties – their mass, spin, and electric charge.
 10:08: ... astrophysical black holes are also expected to have no electric charge, so mass and spin should define everything – including the nature of the ...


20190903: Is Earth's Magnetic Field Reversing?
 00:38: Magnetic fields exert a force on moving charged particles, causing them to spiral around those force lines.
 00:46: Now, that’s helpful, because Earth is constantly bombarded by very fast moving charged particles, especially coming from the Sun.
 03:15: Alternatively, flows of many charged particles like electrons – so electrical currents  can produce magnetic fields.


20190313: Will You Travel to Space?
 09:17: ... are willing to pay the quarter of a million dollars that we currently charge, then we can start building more and more spaceships. And as you build ...


20190306: The Impossibility of Perpetual Motion Machines
 13:47: ... the stars, and also from individual electrons either bumping into other charged particles or circling in magnetic fields Fortunately we can model that ...


20190207: Sound Waves from the Beginning of Time
 03:08: ... interaction between the charged particles of the plasma via the trapped photons meant that ripples in ...


20190130: Perpetual Motion From Negative Mass?
 03:41: That’s the opposite to electric charge, in which like charges repel and opposite charges attract.
 12:15: It also implies that ALL fundamental forces have their directions flipped by the action of the charge of the gravitational field.


20190124: The Crisis in Cosmology
 15:12: ...the simultaneous reversal of charge, parity, and time.


20190116: Our Antimatter, Mirrored, TimeReversed Universe
 00:03: ... distinguish our universe from one that is a perfect mirror opposite in charge handedness and the direction of time but one by one these symmetries ...
 02:02: ... threat to an even deeper symmetry cpt symmetry the combined flipping of charge parity and time and this symmetry lies at the foundations of quantum ...
 03:02: ... and other antiatoms sending matter to antimatter is the C part of cpt charge conjugation all charges switch side electric charge but also quark color ...
 08:43: ... particles in a rewinding universe actually look like they underwent a charge parity ...
 10:54: ... as experiments found broken symmetries one, by one the first parity then charge parity the hallow'd CPT symmetry looked in danger unless we gave up on ...


20181220: Why String Theory is Wrong
 04:07: Momentum in that loop dimension has the exact behavior of electric charge, with the direction of rotation determining the sign of the charge.
 04:17: It was an incredible discovery and a beautiful one. It even made a prediction: the ratio between the mass of the electric charge and the electron.
 04:26: Assuming the experimentally measured value for the electric charge, the corresponding electron mass should be around five kilograms?
 15:37: ... reflection of our universe, not only are spatial coordinates flipped, charges are also reversed and in fact time is reversed ...
 16:28: ... when you reverse parity charges and time do you get a universe that behaves like, ours one full of ...


20181212: Quantum Physics in a Mirror Universe
 00:02: ... parity is a discrete symmetry other types of discrete symmetries include charge conjugation flipping the sign of the electric charge and time reversal ...


20181031: Are Virtual Particles A New Layer of Reality?
 05:18: ... with their real counterparts in particular, quantum numbers like charge and spin, but they don't need to obey Einstein's relationship between ...


20181018: What are the Strings in String Theory?
 07:24: And those modes, in turn, define particle properties like electric charge and spin.


20181010: Computing a Universe Simulation
 13:15: But that's radio, which can interact strongly with the rare charged electrons and protons in intergalactic space.


20180920: Quantum Gravity and the Hardest Problem in Physics
 09:33: ... electrodynamics, the electron has a selfinteraction due to its electric charge messing with the surrounding electromagnetic ...
 10:31: ... example, measurement of the mass and charge of an electron renormalizes quantum electrodynamics to allow incredibly ...


20180905: The Black Hole Entropy Enigma
 02:08: From the point of view of the outside universe, black holes can only have three properties mass, spin, and electric charge.
 04:59: We can easily measure its mass, spin, and electric charge, and according to the nohair theorem that's all there is to know.


20180823: How Will the Universe End?
 14:19: If you have your mass and charge distributed exactly the same, then g equals 1.
 14:24: If, by contrast, you have an infinitely thin shell of charge surrounding a mass, your g equals 5/3.
 14:35: Classically, we assumed the electron was a ball of charged stuff, hence g equals 1.
 14:44: This, in essence, is because his equation has the charge and mass distributed differently.
 14:49: QED further tweaks this by showing the charge can smear by something called the vacuum polarization.


20180815: Quantum Theory's Most Incredible Prediction
 01:13: ... calculations of QED describe how this field interacts with charged particles to give us the electromagnetic force, which binds electrons to ...
 01:28: ... complicated description of electromagnetism than the simple opposite charges attract, like charges repel of classical ...
 03:03: Magnetic fields are produced by moving electric charges.
 03:06: ... perfect dipole field is produced by charges moving in circles, for example, a loop of wire with an electric current ...
 03:41: ... seem intuitive if you think of them as tiny balls of rotating electric charge, except electrons aren't balls and they aren't really ...
 04:02: Nonetheless, electrons do have a sort of intrinsic, angular momentum, a fundamental quantum spin that is as intrinsic as mass and charge.
 04:49: Thinking of electrons as little bar magnets or as rotating balls of charge is a nice starting point.
 05:09: ... twice the value you'd expect for a tiny classical sphere with the same charge and angular momentum as an ...
 11:32: This is the fundamental constant governing the strength of the electromagnetic interaction of charged particles.


20180801: How Close To The Sun Can Humanity Get?
 02:19: Charged particles traveling at nearly 1% the speed of light bombarded the earth.
 04:51: ... will capture the most energetic particles of the solar wind charged particles like electrons, protons, and heavier nuclei, measuring their ...


20180711: Quantum Invariance & The Origin of The Standard Model
 08:17: We also learned about the origin of electric charge, which we now see as a coupling turn.
 08:24: Any particle that has this kind of charge will interact with and be affected by the electromagnetic field and be granted local phase invariance.
 08:35: In order to have this particular type of local phase invariance, particles must possess electric charge.
 08:48: In this case, the symmetry is local phase invariance and the conserved quantity is electric charge.
 09:28: But what about all those fundamental particles without electric charge?


20180704: Will A New Neutrino Change The Standard Model?
 02:10: ... going to drop through the standard model of particle physics, electric charge and antimatter, the bizarreness of quantum chirality and the Higgs ...
 03:02: These have far lower mass, and unlike quarks and leptons, they have no electric charge, hence neutrino or little neutral one.
 03:16: An antimatter version of a particle has the same mass and the opposite electric charge.
 03:20: So an electron has a charge of negative 1 and an antielectron has a charge of plus 1.
 03:26: Neutrinos don't have charge, so what's the difference between a neutrino and an antineutrino?
 05:00: Like electric charge, chirality is also reversed in antimatter.
 05:05: ... example, both left and right chiral negatively charged electrons have their own positively charged antimatter particles, which ...


20180620: The Black Hole Information Paradox
 01:54: It states that black holes can only exhibit three properties mass, electric charge, and angular momentum.
 12:52: EpsilonJ asked, what would happen if you fired a continuous beam of electrons at a black hole and how would the charge affect the Penrose diagram?
 13:03: If you keep injecting charge into a black hole, then it does maintain an electric charge.
 13:07: That charge only decays if the black hole is left to its own devices.
 13:11: And it turns out that a charged black hole has a pretty weird Penrose diagram.
 13:20: ... electric charge within the black hole produces a negative pressure that actually halts ...
 13:29: In the mathematics, it looks as though anything falling into a charged black hole is ejected into a separate universe.
 13:41: ... how it can be that the outside of a black hole can feel its electric charge given that the electromagnetic field is communicated by photons and ...
 13:53: ... we talked about a black hole's electric charge in terms of the classical electromagnetic field which has an existence ...
 14:35: ... particles can escape a black hole to communicate the influence of the charge within, but it's important not to take the existence of these particles ...
 14:44: The electromagnetic field outside the black hole knows about the charge inside the black hole.


20180613: What Survives Inside A Black Hole?
 01:09: ... properties are mass, electric charge, and angular momentum, or at least this is the proposition behind the ...
 01:45: ... when he proposed that no other properties besides mass, electric charge, and angular momentum should emerge from beneath the event ...
 02:28: ... that went into the black hole are its massenergy content, electric charge, and angular ...
 03:06: So how does mass, electric charge, and angular momentum communicate their influence across the uncrossable horizon?
 05:47: ... electric flux passing through a closed surface depends on the amount of charge interior to that ...
 05:56: The universe remembers the total charge that exists in the region of space enclosed by the surface.
 06:04: This means that the electric field above the event horizon of a black hole remembers all of the electric charge that fell through that surface.
 06:12: Black holes act as though their charge is spread across the event horizon.
 07:04: It applies to any shaped surface surrounding any shaped mass or charge.
 07:15: They are infinite in range and they arise from conserved quantities, namely mass and charge.
 07:34: ... forces have infinite range, and so Gauss's law demands that the mass and charge content of any region of space are remembered in the gravitational and ...
 07:50: ... mass and charge are fundamentally conserved quantities, the only way to change the ...
 08:08: By the way, it's worth mentioning that real black holes out there in the universe are never going to have a net electric charge.
 08:15: ... black hole with nonzero charge will quickly attract particles with the opposite charge until positive ...
 09:36: I hope I've given you a sense of why mass, charge, and angular momentum are remembered by the space outside a black hole.


20180523: Why Quantum Information is Never Destroyed
 02:05: For example, we could reverse all electric charges, or we could flip the xaxis by looking in a mirror, or we could make time run backwards.


20180516: Noether's Theorem and The Symmetries of Reality
 07:31: For example, another conserved quantity in physics is electric charge.
 07:54: This symmetry leads to the conservation of electric charge and electric current.
 08:08: They predict a rich family of conserved charges that govern the interactions of the particles of the standard model.
 08:14: For example, the color charge of quantum chromodynamics describes the strong interaction between quarks and gluons.


20180411: The Physics of Life (ft. It's Okay to be Smart & PBS Eons!)
 11:38: That emission looks like a straightforward quantum process, analogous to photon emission by an accelerating electric charge.


20180404: The Unruh Effect
 09:06: A charged particle accelerating in a magnetic field emits radiation, bremsstrahlung radiation.
 09:13: An inertial observer sees the charged particle itself radiating, its energy extracted from the magnetic field.
 09:19: But an observer accelerating with that charged particle sees it absorbing Unruh particles and then spitting them out again.


20180110: What Do Stars Sound Like?
 12:33: As Felix realizes, light is not electrically charged, and so it isn't affected by EM fields.
 12:39: In fact, the magnetic field of a gamma ray burst focuses charged particles electrons and the nuclei of the exploding star.
 12:56: The charged particles spiral around the axial magnetic fields and emit photons as they do.
 13:17: ... of the light emitted in the same direction as the near light speed charged particles of the ...


20171019: The Nature of Nothing
 04:33: For example, QFT describes the electromagnetic force as the exchange of virtual photons between charged particles.
 07:58: ... partially shields the orbiting electrons from the positive charge of the nucleus, with the amount of shielding being slightly different ...


20170928: Are the Fundamental Constants Changing?
 03:42: In the language of quantum field theory, it's the coupling strength between the electromagnetic field and a charged field like the electron field.


20170830: White Holes
 02:45: ... a black hole the simplest black possible, one without spin, without charge, or without change, an eternal black that doesn't grow or shrink and has ...


20170810: The OneElectron Universe
 00:33: The fateful conversation began, Feynman, I know why all electrons have the same charge and the same mass.
 02:04: ... had troubled Wheeler that they are all identical, exactly the same charge, exactly the same mass, exactly the same ...
 03:45: Well, moving charged particles also produce a current an electric currents.
 03:51: The direction, or sign, of that current depends on the direction of motion, but also on the sign of the charge.
 03:58: ... example, if a negatively charged electron is moving to the left, it produces some current, I. Then, an ...
 04:15: And a positively charged positron moving to the left also produces the same opposite signed minus I current.
 04:24: ... direction of the motion of the electron, or if you give it the opposite charge by turning it into a ...
 04:43: ... of motion appears reversed, which has the same effect as flipping its charge. ...
 05:09: C is charge conjugation, so flipping the sign of the charge.
 05:27: ... if you make all of these changes at the same time flip the charge, invert the parity, reverse time a particle should end up back where it ...
 05:37: But if you just flip the charge and in parity so do a CP transformation you still have to reverse time again to get back where you started.
 05:56: But a charge flip just turns a particle into its antimatter counterpart.


20170726: The Secrets of Feynman Diagrams
 04:47: Charge must also be conserved.
 04:56: If an electron and positron both go in, then their charges cancel.
 05:01: So a zero charge photon must leave.
 05:04: Similarly, if a photon creates a negatively charged electron, it must also create a positively charged positron.
 05:11: ... more complex ways in which ingoing and outgoing particles can balance charge, but as we'll see, all of these can be built up from this one ...


20170719: The Real Star Wars
 17:02: So the electric charge, which in turn depends on the fine structure constant.


20170712: Solving the Impossible in Quantum Field Theory
 10:27: ... quantum field theory for example, the infinite shielding of electric charge due to virtual particleantiparticle pairs popping into and out of ...


20170707: Feynman's Infinite Quantum Paths
 14:44: This socalled charge parity or CP violation has been seen in experiments, implying that the universe does treat antimatter differently to matter.


20170621: AntiMatter and Quantum Relativity
 02:47: For example, an electron's spin causes them to align themselves with magnetic fields, just like a rotating electric charge would.
 07:57: It would also act like it had the opposite electric charge to the electron, a positive charge.
 10:27: Just as with the holes in the Dirac sea, antimatter particles have the same mass as their counterparts, but opposite charge.


20170419: The Oh My God Particle
 03:48: These cascades are called air showers, streams of charged particles cause the air to fluoresce, a glow that can be seen by specialized telescopes.


20170405: Telescopes on the Moon
 05:00: Tiny shards of electrically charged glass in other words, moondust.
 05:17: Hit by sunlight, tiny regolith particles build up electric charge, and so repel each other into dust fountains in the low lunar gravity.
 11:24: One possibility could be in a ReissnerNordstrom black hole, so one with electric charge, but no spin.
 11:33: ... electric field in a charged black hole at the singularity is expected to produce an ...


20170315: Time Crystals!
 02:01: Wilczek came up with a simple model in which charged particles in a superconducting ring break what we call continuous time translational symmetry.
 04:03: Set up a chain of ions, so electrically charged atoms.


20170104: How to See Black Holes + Kugelblitz Challenge Answer
 10:41: ... the sun, but hey, we just built an infinitely strong Dyson sphere and charged it with an impossible amount of ...


20161214: Escape The Kugelblitz Challenge
 01:11: The Penrose diagram we looked at represents a Schwarchild black hole so no electric charge and no rotation, but also an eternal black hole.


20161208: What Happens at the Event Horizon?
 11:13: We'll also come back to what happens if we set the black hole spinning or add some electric charge.


20161130: Pilot Wave Theory and Quantum Realism
 14:30: Well, to create and sustain a magnetic field, you need some charge that's moving or spinning in some way.


20161102: Quantum Vortices and Superconductivity + Drake Equation Challenge Answers
 02:11: ... of superconductors and superfluids, and providing new ways to move charge, spin, and even information around ...


20161019: The First Humans on Mars
 09:36: Black holes exhibit only three properties mass, electric charge, and spin.


20161012: Black Holes from the Dawn of Time
 12:16: ... with each other, water is also a dipole, meaning it has more positive charge on one side and more negative on the ...


20160622: Planck's Constant and The Origin of Quantum Mechanics
 03:14: Accelerated charges produce electromagnetic radiation light.
 03:19: And so an object made of jiggling charged particles, like electrons and protons, glows.


20160330: Pulsar Starquakes Make Fast Radio Bursts? + Challenge Winners!
 04:21: ... and helium nuclei, the other common charged particles hanging around the universe at this time, have much smaller ...


20160127: The Origin of Matter and Time
 06:50: At each interaction, particles exchange energy, charge, and other properties that result in change.


20151216: The Higgs Mechanism Explained
 01:43: ... and fields interact with each other, transferring energy, momentum, charge, et cetera, between particles and ...
 04:26: ... like regular electric charge, which lets all electrons feel the electromagnetic force, except in this ...
 04:58: But where does this charge come from, and where is it go to?
 05:17: ... weak hypercharge, but manages to take on all possible values of this charge ...
 05:53: ... invisible and infinite ocean of some sort of charge that we've never heard of all invented so that electrons can be left and ...


20151209: How to Build a Black Hole
 10:24: The black hole retains mass, electric charge, and spin.


20151015: 5 REAL Possibilities for Interstellar Travel
 05:28: Annihilate a proton and an antiproton, and you get charged pions moving at near light speed.


20151007: The Speed of Light is NOT About Light
 03:00: Well, magnetism comes from moving electric charges.


20150819: Do Events Inside Black Holes Happen?
 11:17: ... rotating black holes, charged black holes, black hole evaporation, what goes on around black holes, ...
