
20221208: How Are Quasiparticles Different From Particles?
 08:40: ... forming a nucleus and electrons bound to that nucleus by the exchange of virtual ...


20221123: How To See Black Holes By Catching Neutrinos
 12:47: For those of you who don’t know, a VPN is a virtual private network.


20221116: Are there Undiscovered Elements Beyond The Periodic Table?
 07:08: It involves sending virtual quark packets  mesons  between the nucleons.


20221109: What If Humanity Is Among The First Spacefaring Civilizations?
 09:47: ... if there are both longlived habitable planets and many hard steps, then virtually all civilization will result from very drawnout evolutionary processes ...


20220928: Why Is 1/137 One of the Greatest Unsolved Problems In Physics?
 06:02: ... probability at each vertex, each interaction between electron and virtual photon, adjusted by all these other parameters I ...


20220921: Science of the James Webb Telescope Explained!
 13:09: Instead, nucleons continuously spit out virtual pi and rho mesons  quark, antiquark pairs  which are then absorbed by neighboring nucleons.


20220824: What Makes The Strong Force Strong?
 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.
 06:42: A pair of quarks bound into, say, a pion, are connected by a gluon field, also describable as a constant exchange of virtual gluons.
 17:53: ... Jahrmarkt and Gabriel Monteiro de Castro Both ask the same question: if virtual particles don’t actually exist, but instead are a calculation tool to ...
 18:07: After all, Hawking radiation is sometimes portrayed as a virtual particleantiparticle pair being separated by a black hole event horizon.
 18:15: ... the answer is that the story about separation of virtual particles by the event horizon is a meant to be an intuitive picture of ...


20220817: What If Dark Energy is a New Quantum Field?
 00:36: ... Empty space buzzes with random activity that we sometimes describe as virtual particles popping into and out of existence, driving accelerated ...


20220803: What Happens Inside a Proton?
 01:31: ... nucleon is a roiling, shifting swarm of virtual quarks and gluons that just LOOKS like three quarks from the ...
 04:17: ... with the electromagnetic field  emitting and absorbing a virtual photon. And there’s a set probability of that happening each time ...
 05:31: ... going to interact by the strong force, which is mediated via virtual gluon of the gluon field rather than virtual photons ...
 07:07: ... the idea of particles altogether. See, it turns out that the virtual particles that we were using to calculate particle interactions ...
 07:53: ... are way too tumultuous to be easily approximated by virtual particles. Instead we have to try to model the field more ...
 08:30: ... reduce the number of field configurations by approximating them as virtual particles. But for QCD we have to stick with fields, so we ...
 14:08: ... of the quantum fields. For one thing, because it doesn’t use virtual particles at all, but rather simulates the quantum field more ...


20220622: Is Interstellar Travel Impossible?
 15:16: ... abstract idea including imaginary replica black holes connected by virtual ...
 19:10: Otinane Yos asks whether we can be sure that virtual particle  antiparticle pairs get separated near a Black Hole event horizon.
 19:26: And most of those lines of reasoning say nothing about virtual pairs of particles.
 19:36: ... virtual particle picture is a sort of colloquial interpretation of what’s going ...


20220615: Can Wormholes Solve The Black Hole Information Paradox?
 03:20: ... radiation is that the black hole is swallowing and emitting virtual particles. We can think about the vacuum of space as being ...
 12:09: ... what’s the result? Did these virtual, wormholey topologies solve the information paradox? Well, it ...


20220427: How the Higgs Mechanism Give Things Mass
 16:02: ... model particles that could have a ghostly presence as virtual particles in the energy field of the boson. The fact that FermiLab ...


20220210: The Nature of Space and Time AMA
 00:03: ... vacuum energy density the old one has the same kind of behavior of virtual particles uh it has the same amount of dark energy quickly okay the ...


20220127: How Does Gravity Escape A Black Hole?
 06:16: ... force is communicated between charged particles by transferring virtual photons  ephemeral excitations in the electromagnetic ...
 06:54: There’s a bit of a misconception in how we think about virtual particles.
 07:02: Virtual particles aren’t localized like that.
 07:08: They interact by exchanging a virtual photon.
 07:10: Or more precisely, they exchange the sum of all possible virtual photons.
 07:33: ... if gravity is really mediated by virtual gravitons, then those gravitons don’t emerge from the location of the ...
 07:44: The gravitational field around the black hole is already abuzz with virtual gravitons.
 07:55: That’s easy  these are virtual particles, and in quantum field theory, virtual particles are not restricted by the speed of light.
 08:06: ... between particles result from the sum of all virtual particle interactions, possible and Impossible, and the speed of light ...
 08:25: But if we’re describing the gravitational field as being built up by virtual gravitons then the event horizon is no barrier at all.
 10:06: ... gravity is communicated by the curvature of spacetime or by virtual gravitons, we maintain a causal connection to the mass that generated ...


20220119: How To Build The Universe in a Computer
 10:14: And then we have cosmological simulations which create entire virtual universes, from the moment the first atoms formed to the modern day.


20220112: How To Simulate The Universe With DFT
 19:55: Basically, this is a planetsized computer that could run a virtual world supporting our uploaded minds as virtual intelligences.


20211220: What Happens If A Black Hole Hits Earth?
 02:27: ... on when they formed, PBHs could have virtually any mass  from tiny ‘micro’ black holes all the way up to the ...


20211210: 2021 End of Year AMA!
 00:02: ... or repelled from each other are so influenced by the exchange of virtual particles virtual bosons um in the case of say an electron and a ...


20211005: Why Magnetic Monopoles SHOULD Exist
 07:56: ... and Dirac argued that this makes it a mathematical figment, kind of like virtual ...


20210616: Can Space Be Infinitely Divided?
 08:37: ... production. The act of localiuzing the electron causes pairs of virtual electrons and positrons to appear around it. The ...
 09:58: ... is fundamentally uncertain. In the same way that you get virtual particles on subatomic scales, on the Planck scale you ...


20210421: The NEW Warp Drive Possibilities
 14:18: The probability that a particle will interact with other massive virtual particles is proportional to the square of that particle’s own mass.
 14:52: That said, there are other ways to track a particle’s interactions with virtual particles.
 15:01: ... of those decays products are sensitive to the complex interactions with virtual particles that happen during the ...


20210407: Why the Muon g2 Results Are So Exciting!
 04:33: In this theory, electromagnetic interactions result from charge particles communicating by exchanging virtual photons.
 04:47: For example, a pair of electrons could repel each other by exchanging one virtual photon, or two virtual photons, or three et cetera.
 04:56: All those virtual photons could do something weird like momentarily becoming an electronpositron pair.
 05:14: For a deeper dive in Feynman diagrams, virtual particles, and quantum electrodynamics, we have you covered, episode list in the description.
 05:48: ... next simplest is for the electron to emit a virtual photon just prior to absorbing the magnetic field photon, and then ...
 07:43: The quantum vacuum is seething with an incredible variety of possible virtual particles.
 08:19: The probability of interaction between a particle and some massive virtual particle is proportional to mass squared.
 08:31: It's 40,000 times more likely than the electron to encounter, say a virtual Higgs boson, or virtual proton or other hadrons.
 08:39: And it's 40,000 times more likely to encounter any completely unknown virtual particles that might be hiding out there.


20200728: What is a Theory of Everything: Livestream
 00:00: ... story i learned from my friend john lanier one of the pioneers of virtual reality of how feynman was doing physics near the end of his life he's ...


20200622: Building Black Holes in a Lab
 05:25: ... mass as a type of radiation. The popular description is that pairs of virtual particles appear near the event horizon and are separated  one escapes ...


20200527: Does Gravity Require Extra Dimensions?
 11:58: This is the negative pressure due to the exclusion of quantum vacuum modes, or virtual particles, between two very closely separated plates.


20200428: Space Time Livestream: Ask Matt Anything
 00:00: ... if I can describe how dark energy and evaporating black holes with virtual particles do not violate conservation laws so let's start with let's ...


20200211: Are Axions Dark Matter?
 08:05: ... would do this by generating pairs of virtual quarks which then decay into photons  the socalled Primakoff effect. ...


20200203: Are there Infinite Versions of You?
 15:00: Imagine an interaction where an electron emits a virtual photon which then deflects another particles  say, a proton.
 15:08: ... direction of the flow of time is irrelevant from the perspective of the virtual photon  what matters is the structure of the ...
 15:42: ... t channel is where 2 particles scatter off each other by exchanging a virtual particle, while the schannel is where the particles annihilate each ...


20200127: Hacking the Nature of Reality
 02:16: ... are calculated by adding up the exchanges of infinite number of virtual ...
 06:47: Remember, that quantum field theory fastidiously adds together a complete set of virtual interactions that contribute to the real interaction.
 07:23: But in order to avoid those sums of Feynman diagrams, Smatrix theory also relies on symmetries between those virtual interactions.
 08:05: ... ways this can happen as follows: 1) the ingoing particles exchange a virtual particle which deflects or transforms them into the outgoing particles  ...
 10:27: Standard QCD employs sums over large numbers of intermediate virtual states.
 10:33: And as we discussed in our episode on virtual particles, the physicalness of these states are questionable at best.


20200106: How To Detect a Neutrino
 04:24: ... ♪ (𝘤𝘰𝘯𝘵𝘦𝘮𝘱𝘭𝘢𝘵𝘪𝘷𝘦 𝘦𝘭𝘦𝘤𝘵𝘳𝘪𝘤 𝘱𝘪𝘢𝘯𝘰 𝘴𝘰𝘧𝘵𝘭𝘺 𝘢𝘳𝘱𝘦𝘨𝘨𝘪𝘢𝘵𝘦𝘴) ♪ or, truly, a virtual boson. It exists only for an instant  ♪ (𝘤𝘰𝘯𝘵𝘦𝘮𝘱𝘭𝘢𝘵𝘪𝘷𝘦 𝘦𝘭𝘦𝘤𝘵𝘳𝘪𝘤 𝘱𝘪𝘢𝘯𝘰 ...
 04:59: ♪ ♪ ♪ ♪ So: the briefer the lifetime of this virtual boson, the more energy it's allowed to borrow.


20190819: What Happened Before the Big Bang?
 02:58: You can think of a field with a high field strength as being full of virtual particles.


20190725: Deciphering The Vast Scale of the Universe
 05:52: ... Hayden have turned that dome into a spaceship. It can fly us through a virtual universe built from the most complete 3D atlas of our Universe ever ...


20190109: Are Dark Matter And Dark Energy The Same?
 06:22: ... he programs a virtual universe into his computer with both positive and negative mass ...


20181107: Why String Theory is Right
 14:14: ... one of the most misunderstood concepts in quantum mechanics, the idea of virtual particles and their tenuous connection to ...
 14:33: Aren't they virtual?
 14:44: ... fluctuations can be approximated as the sum of many virtual particles, but the particles themselves are just convenient mathematical ...
 14:56: Eddie Mitch asked whether the virtual particles are required to explain the Casimir force.
 15:02: ... Casimir effect is sometimes explained as resulting from the exclusion of virtual particles between two very closely separated conducting plates which ...
 15:14: ... it isn't but if it is, then it's still misleading to attribute it to virtual ...


20181031: Are Virtual Particles A New Layer of Reality?
 00:02: Let me tell you a story about virtual particles.
 00:21: Near black holes, virtual matter and antimatter pairs are separated by the event horizon to create Hawking radiation.
 00:29: And every time two particles interact, an infinite number of virtual particles mediate infinite versions of that one interaction.
 00:39: Virtual particles sound pretty cool, I guess, but is this really how they work?
 00:45: Seriously, what are virtual particles?
 01:26: A more recent mathematical hack is the virtual particle.
 01:41: So will virtual particles also prove to represent a new underlying aspect of reality?
 01:57: First, let's get to the origin of virtual particles.
 03:12: Those interactions are mediated by virtual particles.
 03:16: In that sense, virtual particles are the building blocks of our approximation of the behavior of quantum fields.
 03:25: ... one photon worth of quantum properties in a single packet that we call a virtual ...
 03:54: Every one of these interactions is described with a simple excitation and transfer of particles virtual particles.
 04:12: We call these idealized interactions intermediate states or virtual states of the field.
 04:22: The virtual particles never exist independently.
 04:25: Instead, virtual particles are the mathematical building blocks we use to approximate the complex states of interacting fields.
 04:53: All those that both start and end within the diagram are virtual particles.
 04:58: ... field theory calculations, but they also add to the misconception about virtual ...
 05:09: They sure make it look like virtual particles are doing regular particle stuff like traveling through space but that's just not the case.
 05:18: ... Virtual particles share some properties with their real counterparts in ...
 05:45: Virtual particles are our mathematical representation of the quantum mechanical behavior of fields, and that behavior is weird.
 06:00: One electron throws a virtual photon at the other one causing them to be deflected from each other like a game of quantum dodgeball.
 06:17: Let's look at the fine and diagram of a single virtual photon passing from electron to positron.
 06:23: ... effect of this, you add together the possible effect of every possible virtual photon being emitted by the electron and absorbed by the ...
 06:50: These are the virtual photons that ultimately provide the attractive force.
 07:03: These virtual particles sort of exist everywhere at once, which is confusing.
 07:09: ... one of these infinite possible virtual particles represents a quantum of energy in a single possible ...
 07:20: In a way, a virtual particle represents a pure excitation of the field, an idealized case of perfectly defined momentum.
 07:29: The Heisenberg uncertainty principle tells us that the perfectly defined momenta of virtual particles means completely undefined position.
 07:53: Our virtual photon doesn't have a location, so it doesn't travel a real path.
 08:16: No individual virtual photon can be credited with producing the attractive force.
 08:22: In fact, you only see that force in the sum of all possible virtual photons over all possible Feynman diagrams.
 08:42: So that's the deal with virtual particles in particle interactions, but we also hear about the role of virtual particles in a complete vacuum.
 08:52: ... might have heard the quantum vacuum described as his roiling ocean of virtual particleantiparticle pairs popping into and out of existence, the ...
 10:48: Virtual particles are not popping into and out of existence in the absence of any else.
 11:03: Stephen Hawking himself was the first to use virtual particles as an intuitive way to describe his radiation.
 11:11: ... painted a picture of virtual matterantimatter pairs being separated by the black hole event horizon, ...
 11:50: ... on these, and just like with Hawking radiation, you don't need for virtual particles to have an independent existence to explain these ...
 12:00: So to recap, virtual particles are best thought of as a mathematical device to represent the behavior of quantum fields.
 12:08: ... original idea of virtual particles came about as a calculation tool in perturbation theory as we ...
 12:42: So what about virtual particles?
 12:53: It turns out there is a version of quantum field theory that doesn't use virtual particles at all.
 13:05: It doesn't rely on perturbation theory, and so it doesn't use virtual particles while ultimately giving the same results.
 13:13: Ergo, virtual particles are probably just a mathematical artifact.
 13:17: There is no good reason to believe that virtual particles exist outside the math we use to approximate the behavior of quantum fields.


20181003: How to Detect Extra Dimensions
 14:43: ... and quantum mechanics are both right, then we should have Plancklength virtual black holes popping into and out of ...


20180920: Quantum Gravity and the Hardest Problem in Physics
 15:01: VoodooD0g points out that the vacuum isn't really empty, what, with all the virtual particles popping into and out of existence.
 15:16: The phantom virtual particles represent both the absence of particles and every possibility of particles.


20180823: How Will the Universe End?
 16:20: ... fit maths randomly to the observations when we come up with stuff like virtual particles and that it's so weird that that actually ...


20180815: Quantum Theory's Most Incredible Prediction
 07:22: So one way to think about this quantum buzz is with virtual photons.
 07:36: In the case of electromagnetism, those interactions are mediated by virtual photons, which are just a mathematical way to describe quantum buzz.
 07:45: Every interaction with virtual photons that can happen, does, at least in a sense.
 08:17: They represent the possible interactions of the quantum field by way of virtual photons.
 08:47: The electron first emits a virtual photon, then gets deflected, then reabsorbs the virtual photon.
 09:50: ... ways the electron can interact with the EM field, with crazy networks of virtual particles and virtual matter, antimatter loops between the real ingoing ...


20180620: The Black Hole Information Paradox
 14:01: But quantumfield theory imagines the electromagnetic force as being transmitted by virtual photons.
 14:07: Now it's important to note the distinction between virtual photons and real photons.
 14:11: Virtual particles in general are just a way to mathematically account for the infinite ways a quantum field can communicate its influence.
 14:19: Virtual particles don't have the same restrictions as regular particles.
 14:35: ... this picture, virtual particles can escape a black hole to communicate the influence of the ...
 14:49: ... whether that's because of virtualparticle interaction with the interior or just the persistence of the field at ...


20180315: Hawking Radiation
 01:54: ... pairs of virtual particles, matter and antimatter, spontaneously appear and then ...
 03:17: And those fluctuations give us what we think of as virtual particles.
 03:21: Now don't take the existence of virtual particles too seriously.
 03:51: ... frequency modes, which you can crudely think of as a balance between virtual matter and antimatter ...
 04:03: These all virtually annihilate or cancel out so that no real particles exist.
 08:19: It's fair to interpret this mixing as the promotion of what were once virtual particles into reality.


20180124: The End of the Habitable Zone
 11:56: If the event horizon swallows one half of a virtual matter antimatter pair, then how does the black hole lose mass?


20180117: Horizon Radiation
 09:22: As discussed in a previous episode, we can think of the vacuum as a sea of virtual particles.


20171129: Citizen Science + ZeroPoint Challenge Answer
 06:57: ... of the vacuum energy density comes from assuming that there are no virtual photons above a certain cut of ...
 08:32: ... it tells us that the simplistic approach of choosing the right maximum virtual photon frequency definitely can't give us the vacuum energy that we see ...
 08:42: ... interactions that require the exchange of much shorter wavelength virtual ...
 09:06: That proves the existence of virtual photons with wavelengths smaller than the plate separation.


20171122: Suicide Space Robots
 12:46: Hawking radiation is related to this whole vacuum energy virtual particle thing.


20171108: ZeroPoint Energy Demystified
 04:22: If you bring a pair of conducting plates very close together, a proportion of the virtual particles will be excluded from between them.
 06:02: The fact is, any acceleration of a real particle involves a transfer of momentum between real particles via virtual particles.
 06:10: Virtual particles, and hence, the quantum vacuum, mediate all forces.
 09:09: And is this a possible maximum virtual photon frequency, given the results of Casimir experiments?


20171102: The Vacuum Catastrophe
 00:35: Virtual particles appear and vanish from nowhere in seeming violation of our intuitions about the conservation of mass and energy.
 02:55: What if there's a maximum possible frequency for virtual photons?
 03:31: ... if we add up the vacuum energy, including virtual photons, all the way up to the Planck energy, we get a finite number a ...


20171025: The Missing Mass Mystery
 11:02: Last week, we talked about virtual particles, zero point energies and the nature of nothing.
 11:59: ... Zambelli asked whether the annihilation of virtual matter antimatter particles would introduce energy into the universe ...
 12:21: ... also asks, if virtual particles control faster than the speed of light, can't they escape the ...


20171019: The Nature of Nothing
 04:20: ... call these virtual particles, and they seem to be the machinery under the hood of all ...
 04:33: For example, QFT describes the electromagnetic force as the exchange of virtual photons between charged particles.
 04:41: Virtual particles are the links governing all particle interactions in the famous Feynman diagrams.
 04:48: But to properly calculate an interaction of real particles, every imaginable behavior of the connecting virtual particles must be accounted for.
 05:01: For example, in QFT, virtual particles can have any mass and any speed, including speeds faster than light, and can even travel backwards in time.
 05:16: The ambiguous realness of virtual particles seems to grant them some surreal freedoms, but there are restrictions.
 05:24: For example, quantum conservation laws must be obeyed, so most virtual particles are created in particleantiparticle pairs.
 05:33: But the ultimate price is that virtual particles can exist only for the instant allowed by the Heisenberg uncertainty principle.
 05:55: And so virtual photons can exist for any amount of time, long enough to carry the electromagnetic force to any distance.
 06:13: That means there's a limit to how long virtual gluons can exist and travel, which in turn makes the strong nuclear force a very shortrange force.
 06:23: ... can be argued that virtual particles are just a mathematical tool to describe the behavior of a ...
 07:10: ... first hint of the existence of virtual particles came in 1947, when Willis Lamb and Robert Rutherford noticed a ...
 07:50: Virtual particleantiparticle pairs in the space between the orbitals and the nucleus align themselves with the electric field.
 08:15: Another way to hunt for virtual particles is through their bulk effect on the vacuum.
 08:43: He imagined two conducting plates, brought so close together that only certain virtual photons could exist between the plates.
 08:51: ... only resonates with waves of certain frequencies, any nonresonant virtual photon would be excluded, reducing the vacuum energy between the ...
 09:05: However, on the outer surface of the plates, all frequencies of virtual photon are allowed.
 10:53: ... field theory, with its dependence on virtual particles and vacuum fluctuations, is one of the most successful ...


20170810: The OneElectron Universe
 06:49: That virtual particle in the middle may be an electron traveling forwards or backwards in time.
 09:44: ... and an electron influencing each other's momentum by exchanging a virtual photon similar to electronelectron ...
 09:53: ... the electron and positron actually annihilate each other, producing a virtual photon, which then creates a new electronpositron ...


20170802: Dark Flow
 11:57: ... also propagating through the infinite possible interactions within the virtual space of the Feynman ...


20170726: The Secrets of Feynman Diagrams
 06:15: The particles that have their entire existence between vertices within the diagram but don't enter or leave are called virtual particles.
 07:21: ... different stages in the process, or photons momentarily splitting into virtual electronpositron ...
 08:56: ... that intermediate stage between vertices, the electron is a virtual particle, which means we include all possible paths it might take, as ...
 10:41: The most important Feynman diagrams for Bhabha scattering are the two cases involving a single virtual photon.


20170712: Solving the Impossible in Quantum Field Theory
 02:49: In fact, we call it a virtual photon, and it only exists long enough to communicate this force.
 02:55: There are other types of virtual particle whose existence is similarly ambiguous.
 03:31: They exchange a virtual photon this squiggly line here and the two electrons move apart at the end.
 04:09: ... all of the ways that two electrons can deflect involving only a single virtual ...
 05:26: For example, the electrons might exchange just a single virtual photon, but they might also exchange two, or three, or more.
 05:34: The electrons might also emit and reabsorb a virtual photon.
 05:39: Or any of those photons might do something crazy, like momentarily split into a virtual antiparticleparticle pair.
 07:43: ... include exchanging two virtual photons, or one electron emitting and reabsorbing a virtual photon, or ...
 08:21: ... socalled loop interactions, like when a photon momentarily becomes a virtual particleantiparticle pair and then reverts to a photon again, or when ...
 08:41: Electrons are constantly interacting with virtual photons.
 10:27: ... 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
 09:07: ... a photon traveling between two points could spontaneously become a virtual electronpositron pair before they annihilate back into the original ...


20170503: Are We Living in an Ancestor Simulation? ft. Neil deGrasse Tyson
 02:18: ... way that virtual reality now exists, and you know, video games have advanced, it is ...
 03:23: That under certain assumptions, virtual minds should vastly outnumber real minds in our universe.
 03:29: If so, shouldn't we be virtual minds?
 04:05: That we are simulated minds in a virtual universe that has just enough detail to convince us of its reality.
 04:43: ... advanced civilization could do this on such a scale that these sorts of virtual minds vastly outnumber real ...
 05:32: ... simulate an external environment with the fidelity needed to fool the virtual brain that its environment is ...
 09:03: ... if the virtual minds of an ancestor simulation are vastly more common than the minds of ...


20170222: The Eye of Sauron Reveals a Forming Solar System!
 01:42: In the virtual image, the star doesn't even need to be masked.


20170111: The EM Drive: Fact or Fantasy?
 07:28: To exchange momentum with virtual particles over a distance longer than a Planck length, those particles need to become real.


20160914: SelfReplicating Robots and Galactic Domination
 01:38: ... better things to do with its eternity, like turn inwards into complex virtual ...


20160810: How the Quantum Eraser Rewrites the Past


20160622: Planck's Constant and The Origin of Quantum Mechanics
 13:47: So you end up with a set of virtual lenses that can reasonably produce the observations.


20160615: The Strange Universe of Gravitational Lensing
 04:02: Within these simplified virtual universes, we can hunt through vast possibility space.


20150408: Could You Fart Your Way to the Moon?
 06:15: You can attend in person at various cities across the world or virtually online.


20150401: Is the Moon in Majora’s Mask a Black Hole?
 07:33: And if you can't participate in person, you can do so virtually, and it will also be livestreamed.
