New Results in Quantum Tunneling vs. The Speed of Light

Learn More about Brilliant: brilliant.org/SpaceTime/
Paradoxically, the most promising prospects for moving matter around faster than light may be to put a metaphorical brick wall in its way. New efforts in quantum tunneling - both theory and experiment - show that superluminal motion may be possible, while still managing to avoid the paradox of superluminal signaling.Paradoxically, the most promising prospects for moving matter around faster than light may be to put a metaphorical brick wall in its way. New efforts in quantum tunneling - both theory and experiment - show that superluminal motion may be possible, while still managing to avoid the paradox of superluminal signaling.
Sign Up on Patreon to get access to the Space Time Discord!
/ pbsspacetime
Check out the Space Time Merch Store
www.pbsspacetime.com/shop
Sign up for the mailing list to get episode notifications and hear special announcements!
mailchi.mp/1a6eb8f2717d/space...
Watch our original Quantum Tunneling episode here:
• Is Quantum Tunneling F...
Relativistic Tunneling Paper
iopscience.iop.org/article/10...
Nature Paper
www.nature.com/articles/s4158...
Hosted by Matt O'Dowd
Written by Tom Rivlin & Matt O'Dowd
Post-Production by Leonardo Scholzer, Yago Ballarini, Pedro Osinski, Adriano Leal & Stephanie Faria
GFX Visualizations: Ajay Manuel
Directed by Andrew Kornhaber
Assistant Producer: Setare Gholipour
Executive Producers: Eric Brown & Andrew Kornhaber
End Credits Music by J.R.S. Schattenberg: / multidroideka
Special Thanks to Our Patreon Supporters
Big Bang Supporters
Peter Barrett
Nils Anderson
David Neumann
Ari Paul
Charlie
Mrs. Tiffany Poindexter
Leo Koguan
Sandy Wu
Matthew Miller
Ahmad Jodeh
Alexander Tamas
Morgan Hough
Juan Benet
Vinnie Falco
Fabrice Eap
Mark Rosenthal
David Nicklas
Henry Van Styn
Quasar Supporters
Alex Kern
Michael Schneider
Ethan Cohen
Stephen Wilcox
Christina Oegren
Mark Heising
Hank S
Hypernova Supporters
william bryan
Justin Smith
drollere
Joe Moreira
Marc Armstrong
Elizabeth Smith
Scott Gorlick
Nick Berard
Paul Stehr-Green
MuON Marketing
Russell Pope
Ben Delo
Nicholas Newlin
Scott Gray
Антон Кочков
John R. Slavik
Mathew
Donal Botkin
Edmund Fokschaner
Joseph Salomone
Matthew O'Connor
chuck zegar
Jordan Young
m0nk
John Hofmann
Daniel Muzquiz
Timothy McCulloch
Gamma Ray Burst Supporters
Daniel Morgan
Jeremy Soller
Jonathan Conerly
Andre Stechert
Ross Bohner
Farhan Wali
Paul Wood
Kent Durham
jim bartosh
Nubble
Chris Navrides
Scott R Calkins
Carl Scaggs
G Mack
The Mad Mechanic
Ellis Hall
John H. Austin, Jr.
Diana S
Ben Campbell
Lawrence Tholl, DVM
Faraz Khan
Almog Cohen
Alex Edwards
Ádám Kettinger
MD3
Endre Pech
Daniel Jennings
Cameron Sampson
Pratik Mukherjee
Geoffrey Clarion
Adrian Posor
Darren Duncan
Russ Creech
Jeremy Reed
Eric Webster
Steven Sartore
David Johnston
J. King
Michael Barton
Christopher Barron
James Ramsey
Justin Jermyn
Mr T
Andrew Mann
Peter Mertz
Isaac Suttell
Devon Rosenthal
Oliver Flanagan
Bleys Goodson
Robert Walter
Bruce B
Ismael Montecel
Simon Oliphant
Mark Delagasse
Mark Daniel Cohen
Brandon Lattin
Nickolas Andrew Freeman
Protius Protius
Shane Calimlim
Tybie Fitzhugh
Robert Ilardi
Eric Kiebler
Craig Stonaha
Martin Skans
Michael Conroy
Graydon Goss
Frederic Simon
Tonyface
John Robinson
A G
Kevin Lee
Adrian Hatch
Yurii Konovaliuk
John Funai
Cass Costello
Tristan Deloche
Bradley Jenkins
Kyle Hofer
Daniel Stříbrný
Luaan
AlecZero
Vlad Shipulin
Cody
Malte Ubl
King Zeckendorff
Nick Virtue
Scott Gossett
Dan Warren
Patrick Sutton
John Griffith
Daniel Lyons
DFaulk
GrowingViolet
Kevin Warne
Andreas Nautsch
Brandon labonte

[@tbatlas7243]

The universe saves CPU space by not fully rendering particles that aren't being viewed by the player. This leads to entities sometimes glitching through walls.

[@terrymiller111]

The Divine is leet.

[@juzoli]

Every particle is viewed exactly once, when it collides into another particle. A photon is “viewed” when it hits something. Not before, not later. No exceptions.

[@supermaster2012]

@@juzoli not really, an entangled pair of photons allows you to see the same property twice.

[@anarchyantz1564]

Bethesda wont fix it so it is down to us modders to patch the damn thing as usual.

[@tristarnexus]

Next time on PBS: Quantum Rubberbanding.

[@danieljensen2626]

That feel when causality is only highly statistically likely.

[@shubhsrivastava4417]

Just like entropy. Interesting!

[@liggerstuxin1]

Well said and well understood.

[@Carewolf]

Causality IS only statistically guaranteed.

[@shubhsrivastava4417]

Interesting thought: If we consider a hypothetical universe before ours was made, it will have negative flow entropy with respect to our time if we take the entropy of the Big Bang as zero. So, if the pre-universe had reversed flow of entropy then it must also have reversed causality by our hypothesis due to statistical nature of causality. This will cause the pre-universe to have negative flow of entropy and negative causality compared by our time. Negative causality means negative flow of time, in which effect precedes cause. This means that the pre-universe had positive flow of entropy with respect to their flow of time. This doesn't break any laws of physics. Here I am not saying that a pre-universe came before us instead it may be also born along with ours during the Big Bang because they also have a positive entropy/causality ratio just like ours, only the direction of flow of time is reversed. This is shown in the movie 'Tenet'. It may be true? What are your thoughts? Please correct me wherever I may be wrong.

[@arrow1414]

But not impossible, aka, "so that's a yes that "Star Trek" like subspace communication is possibe?"😁

[@FiksIIanzO]

Bug report: Subatomic particles sometimes phase out of bounds when players aren't looking. Maybe something to do with cheaper collision logic while they're culled? --- //It's a long standing legacy code issue. Someone thought it was a good idea to dynamically separate particles based on a physics bug instead of a timer so that stars work properly, and now too much of the project is built upon this little bodge. It's a headache, but the project is long in release and we would have to refactor good half of subatomic scripts to fix that, and I know how many issues will come out of that, so let's just pretend it's a feature and be dome with it. Next universe, I'm firing anyone who even suggests subatomic interactions. PS: If you think this is weird, check out black hole code. Not even I understand why they shrink constantly. -G.

[@burnttoast6974]

the flying spaghetti monster is just the spaghetti code of the universe

[@shepherds314]

This is too accurate 😂

[@LuisSierra42]

The reptile devs must be scared that we are finally figuring out how the simulation works

[@alexganz2582]

This may be the best comment ever made on KZbin. Can we get an award sent this way? Or get a system admin to grant Fiks +10 gold / luck / something?

[@Secret_Takodachi]

I'm tired of testers logging this bug: LISTEN IT'S LOGGED & LABELED "WNF" If it doesn't crash the system, we're not going to fix it! Leave it to the fans, they'll make a mod that addresses the issue.

[@MarkArandjus]

In the true spirit of physics the animator just averaged that car into a sphere :D

[@inzaghi9312]

Ez claps

[@williamdolyniuk7804]

That a STRECH. L.o.l.

[@loturzelrestaurant]

9:30: Sounds like something that just some new invention humans ‚just’ dont have ‚yet’ would fix that and then allow FTL Travel to happen. We know the bridge is on flames, but the invention of fire-immunity-hazard-suits will totally fix this and allow everyone to cross the bridge; if you know what i mean.

[@kaitlyn__L]

It’s not just easier for the maths, it’s easier to animate too! It’s quite an elegant, almost fractal-like, layering of similar but different reasons to regard as a point or small ball. This way it’s just a custom marble model, and a physics sim to get the motion right, especially when settling in the middle. With a modelled car, the animator would have had to do a much more complex sim, or painstaking hand-transferral of keyframes based on the general vibe of the momentum from the sim with a ball.

[@Sponzibobu]

Oh my god, I remember back in college, when I was in a introductory physics class learning about the Heisenberg's Uncertainty Principle, another student asked if FTL teleportation was possible due to the uncertainty of a particle's position. I did not think much about the question at all, but this video makes me wonder if the person who asked that question back then is a true genius! It's amazing how seemingly random curiosities can actually be profound physics mysteries!

[@markthebldr6834]

Think of all the great thoughts a person has in a lifetime but never follows up with them.

[@prakharanand5760]

@@markthebldr6834 I've had many, but I always write down those related to helping me focus on studies, cuz _school_ ...... I still remember when I first heard about time dilation and relativity, I was immersed in those thought experiments, I even wrote them down, some were really good, but now, that curious boy is left nothing but one of the victims of the rotten school system.

[@EvenTheDogAgrees]

Not necessarily a genius, just someone who thinks ahead. I was like that in school as well: when the math teacher explained something, the other kids were just trying to follow along, but I was already thinking a couple steps ahead, placing the new information in context of what we'd already learned, and figuring out the implications. Oddly enough, this thinking ahead does not translate to all areas of life. E.g. I usually don't figure out the plot twist until it's revealed at the end of the movie, even though the director made sure to sprinkle sufficient hints throughout the story.

[@prakharanand5760]

@@EvenTheDogAgrees probably the one thing that makes a genius different is their intuition and the speed at which their brain makes the connections. Like listening to a melody and extending it to compose a whole another composition, just at a really high speed. I've tried doing it, it's nothing special, and I'm probably not a genius cuz that momentum only stays for a mere 2 to 3 seconds.

[@FlyingMonkies325]

Yeh all you have to do is understand something well and then just think about the other ways that you can see it could work using other things you know.

[@S1nwar]

the inverse effect of quantum tunneling is also pretty insane: there is a chance that a particle gets deflected by a potential barrier despite having enough energy to (in the classical case ALWAYS) pass over it

[@alvinuli5174]

Combining both effects, the consequence would be that potential barriers do no determine the motion of the particles.

[@hopeg97]

@@alvinuli5174 "do not determine": correct, but it should be clarified that "do not determine" ≠ "do not affect". For example, clearly, if there were no barrier, you just have the equations of a free particle-with 0 probability of reflection.

[@alvinuli5174]

Taking the concept to its edge, a particle could be free only if there wasn't anything else in the universe. Hence, there wouldn't be any barrier to pass over so there wouldn't be any possible effect. But I don't want to be such radical. Just sayin' that the idea of a free particle is, if not absurd, at least useless, since for such object any equation would be true.

[@hopeg97]

@@alvinuli5174 It's actually very useful, the same way models that involve frictionless surfaces are useful in classical physics. Obviously, no surface is without friction, but some surfaces can be approximated as such; and thought experiments involving collisions of objects moving in frictionless environments (starting with the assumptions of Galilean relativity) lead ultimately to the conservation of momentum, which is observed to match closely with experiments of objects colliding while moving on approximately frictionless surfaces. Similarly, no region of space is ever actually free from external influences, but the results for the free particle (i.e. the complex plane wave) are a good approximation for, say, an electron before it passes through a crystalline nickel diffraction grating, as verified experimentally by the diffraction pattern that appears on the other side of the grating; and the mathematical techniques used in solving the Schrödinger equation for V=0 (using a Fourier transform to solve the problem in momentum space) are also applied in the inverse problem, namely, crystallography, wherein the experimentalist attempts to determine the "grating spacing" of a given material. A model being unrealistic does not mean that any equation would be true; relevant to our discussion, the free particle scenario being less than a perfect description of reality does not mean that the Schrödinger equation permits discontinuity in the wavefunction where there is no discontinuity in the potential. The height of the barrier does not determine reflection, but it does determine probability of reflection, as calculated using the Schrödinger equation. I brought up the free particle in the first place because I was trying to say that the reflection probability is related to the "height" (in units of energy) of the barrier, and as the barrier height goes to zero, so too does the reflection coefficient; thus, it is a convenient mathematical tool. This demonstrates another useful aspect of the free particle scenario: It is a special case of the finite potential barrier in the limit where the barrier height goes to 0, so once you've done the math for a nonzero-height barrier, if you plug 0 in for your height, you should recover the results you expect from the simpler model. That is, in a sense, the essence of physics, and (to some extent) of all science: Do some observations, come up with a simple model, work out the math, make predictions based on the math, compare to experiment, and figure out what must be added to the model to match experiment more closely. Then work out the math on the new model, and if the old model is a special case of the new model, confirm that the new model yields the same results in that special case-if not, you might have done the math wrong. And repeat. My apologies for the long-winded reply.

[@alvinuli5174]

​@@hopeg97 Thank you very much for your well articulated answer! I assume that this thread is about quasi scientific speculation away the boundaries of traditional one. Then I feel confident to aseverate that your are not allowed to let any value go to zero in the context of quantum physics. Where would be moving a free particle? In the vacuum, I suppose. But "we know" that full vacuum is very different to an empty volume of space-time. In such case, since the particle is "alone", it is even most "exposed" to the effect of the virtual particles and other pets of the quantic zoo. Hence the word "free" wouldn't be an adequate adjective for this particle.

[@Taqu3]

I find this tunneling narrative a bit misleading. We don't talk about localized particles here, a part of the particle's wavefunction was always at the observation point to begin with. It is a matter of statics to be able to spot the particle at a distant location far from where its wavefunction peaks. Therefore "particle's" wavefunction does not necessarily travel in space for tunneling to occur.

[@cheezzinator]

Yeah... If there was no barrier, you would still measure some particles arriving earlier (and later) than others. In the limit its possible that an electron suddenly tunnels to the other side of the universe. The important thing here is that this can only happen once the information of the wavefunction has reached the observer. This is what's limited by the speed of light if the universe works the way we currently think it does. There is no such thing as global information.

[@ATMOSK1234]

Doesn't entanglement require global information?

[@XEinstein]

This is the best comment here: it is exactly like you said: the wavefunction is always outside of the barrier so how can you speak about traveling at all. In fact, we can't even speak about a particle at all when it's wavefunction is spread out like that, can we?

[@cheezzinator]

@@ATMOSK1234 Not really, since entanglement can only happen when quantum systems are in contact. In a sense it's the information itself that gets entangled. This information is then carried with the particle and "released" when observed

[@crimzie]

thank gods I'm not the only one who's bothered by this thought

[@pbsspacetime]

Hey Space Timers. The image at 11:07 is now corrected. You can learn about the proper set up of Ramón Ramos, David Spierings, Isabelle Racicot & Aephraim M. Steinberg here: www.nature.com/articles/s41586-020-2490-7?proof=t

[@monblack6382]

CT v gun.

[@hippiecritegymnastics3311]

It is the close-mindedness of physicists themselves in hypothesizing, not the current state of knowledge, that hinders advancement. There is likely helpful research that has sat, unreported to the public, and rebuked without examination by mainstream science awaiting any who seek it at a royal ivy league school.

[@elfpimp1]

@@hippiecritegymnastics3311 I'm forced to agree..

[@undercoveragent9889]

@@hippiecritegymnastics3311 After the pandemic debacle, science has lost its credibility, period. As far as this 'quantum tunneling' nonsense is concerned, why assume the existence of the particle doing the tunneling? I can see how the uncertainty principle could make a 'charge' confused about its position in space so as to make it _appear_ as if some particle has performed a magic trick and actually _moved_ through some barrier but to assume that it is an actual particle doing the tunneling is bad science.

[@loturzelrestaurant]

9:30: Sounds like something that just some new invention humans ‚just’ dont have ‚yet’ would fix that and then allow FTL Travel to happen. We know the bridge is on flames, but the invention of fire-immunity-hazard-suits will totally fix this and allow everyone to cross the bridge; if you know what i mean.

[@farfa2937]

Can it be considered a travel at all? My understanding has always been that the particle just chooses to now exist over there; so no distance is ever traveled, faster or slower than light.

[@Gatitasecsii]

My hypothesis is a jump through dimensions doesn't break the laws of physics because it might look like a huge jump to us but to a higher dimension it's like moving normally

[@Simbosan]

this was my thought, it hasn't transitioned at all. It just turned out to 'be' there. By their logic it is tunneling within the nucleus as well, just in a more common way.

[@kristoffervictorlorico1335]

In this case it does not violate general relativity

[@AidanArentz]

@@Gatitasecsii I think there is something in that. There is a good chance that strange movement to us (like teleportation) is just energy or particles moving through space at a higher dimension. Just theory. But perhaps a good one.

[@kamaredrache]

This only works in interpretations like Orthodox QM, where there are no well-defined positions. In something like de Broglie-Bohm Pilot Wave Theory where there are well-defined positions, the particles do indeed travel through the barrier.

[@bustedrav]

Reminds me of the quote "no matter where you go, there you are" if the wave propogates to the other side of the barrier and the particle ends up there, did the particle really "travel" at all?

[@josephhurdman5588]

Said particle existed at Point A, then existed at Point B. Theoretically, any object in the Universe, regardless of mass, or size, and apparently in a femtosecond, regardless of distance, can do the same...

[@bustedrav]

@@josephhurdman5588 but the wave existed at both point A and point B, only thing different is the probability that it would be observed at one vs the other.

[@esuil]

@@josephhurdman5588 How do you know it existed at Point A?

[@archlich4489]

Buckaroo Banzai might know.

[@rstray4801]

Logan Ninefingers?

[@vampyricon7026]

Late comment but hopefully this is in time: I asked around for other grad students' opinions of the paper, at least the one with the Dirac equation, and they told me that the solution is unphysical precisely because of the acausal propagators. They told me quantum field theory was developed in part because relativistic single-particle quantum mechanics still contains unphysical dynamics such as superluminal tunnelling, and that the results are unlikely to hold up in the full QFT treatment. I've also seen the experimental paper around the time it was published and (iirc) noticed that they used the Schroedinger equation rather than a relativistic treatment. Extrapolating from that to superluminal tunnelling is like claiming that a constant acceleration can accelerate something to superluminal speeds. I asked because I thought the argument that this acausality doesn't matter to be extremely flimsy: One only needs to send a number of particles on the order of 1/(tunnelling probability) to send a superluminal signal.

[@meerjt11]

This is one situation where actually looking at and trying to understand the equations is extremely helpful. The moment I understood why the barrier having a higher energy than the particle caused the probability to flip from a sine wave into an exponential decay still my favourite moment in physics study

[@aniksamiurrahman6365]

The new paper: "The relativistic tunneling flight time may be superluminal, but it does not imply superluminal signaling" and its DOI: 10.1088/1367-2630/abb515 If anyone is interested.

[@GameTimeWhy]

@@babaayman9658 does it?

[@Septicemic-Fugue]

@@GameTimeWhy lol inb4 people start going off about a "firmament"

[@GameTimeWhy]

@@Septicemic-Fugue "you're stupid! Obviously it doesn't prove (your god proof)! It proves my (god proof) is true!"

[@aniksamiurrahman6365]

@@babaayman9658 Have you read the paper? Understood it? At all?

[@Bdix1256]

What's funny is that I'm watching this while procrastinating characterizing wafers that will be used to make tunnel diodes. This video has certainly slowed the tunneling process.

[@justskip4595]

I should be now preparing for math exam that I already passed in 2012.

[@Vatsek]

Go back to work, right now.

[@Bdix1256]

@@Vatsek Nah. I'll do it tomorrow. I don't feel like setting up the 4 point probe.

[@Bdix1256]

@@brettharrison837 I grow the germanium tunnel ingots using a horizontal Bridgman setup

[@ziguirayou]

So in conclusion, FTL travel should be accomplished by the IID (Infinite Improbability Drive). Doug Adams was right again. In your face Albert!

[@mattw7949]

... without all that mucking around with hyperspace.

[@mauijttewaal]

Briljant! Now all we have to do is calculate its improbability;-)

[@keirfarnum6811]

Totally 42!

[@angelmendez-rivera351]

It would not be FTL travel in the first place, though. Quantum tunneling is not a form of movement.

[@ziguirayou]

@@angelmendez-rivera351 What would you call it then? "Non-instantaneous teleportation"? Or "probabilistic weirdness that looks like movement, but isn't quite movement, but for all intents and purposes we could call it movement, for lack of a better understanding of the underlying phenomena"?

[@sebastienpaquin4586]

This makes me think a weird thought, could a particle still tunnel trough "something", even if "something" isn't actually there? IE, does it really NEED something in the way to tunnel trough? In fact, do particles even "travel" at all, or do their wave function just more or less randomly tunnel about every which way, and their path calculated by the Schrodinger equation just the averaging out of all this "(co)motion"? In short, if a particle tunnels trough a forest and there was no tree in the way, did it tunnel at all, or just traversed it?

[@lemonke8132]

Good question, i feel like tunneling without a barrier is literally just a wave function. The only weird thing about tunneling is that the wave function can exit a seemingly impossible valley.

[@urbankobal8154]

Well if there are no barriers, theoretically particle exists everywhere in the universe at the same time, until you make a measurement to determine its position or momentum. A free particle travels in wave-packets which is basically a wave function in a packet.

[@danieljensen2626]

No, there is a fundamental difference in the wavefunction if the potential energy in that region is higher than the actual particle energy, vs in a region with lower energy. In the "classically allowed" region (potential lower than particle energy) the wavefunction forms a standing wave, in the "classically forbidden" region (potential higher than particle energy, i.e. tunneling) the waveform exponentially decays.

[@Khannea]

Space is not what we think it is.

[@ghg8701]

If the particle can't be found where the barrier is, than it increases the probability yo be found where it is not- behinde/ beyond it

[@evelienheerens2879]

I'm not sold on the hidden premise that there is a 'tunneling event'. The tunneling seems to not so much take place as an event rather then as an effect. To have it occur as an event, we would have to observe what happens between the moment we launch the particle and the moment the wave function collapses. For that to happen, we would have to observe it while in wave function and since observation collapses the wave function this is impossible. You'd have to observe it before it's observed. This in turn makes the idea of speed meaningless, all we have is the distance between events, there is no path traversed. I suspect this will turn out like quantum entanglement, not suitable to send messages. Have you ever seen a lightning strike filmed with a high speed camera? First the lightning bolt arcs along many increasingly branching paths, until one of those paths touches the ground and the others disappear, leaving only the path that found it's way being followed. That's what I used to imagine quantum tunneling to look like, every path being followed until the correct one is found and the others are abandoned for the correct one. What if that is exactly what happens to a particle only instead of traveling in only 3 dimensions it travels in 3+x dimensions and the barrier doesn't obstruct the path in all of them?

[@martinlsolden7163]

QT is often not very well explained, the "particle" never moves, it is in all its wave functions destription at all times. What does "move" is the possibillity to observe the "particle" and this "movement" is not yet proven to be bound by causallity.

[@angelmendez-rivera351]

@@martinlsolden7163 Well, calling it "movement" in the first place is misleading.

[@kishorens2787]

Space Time. This question arises by looking at matter and space as two, without understanding the fact that there is no space without matter or time without motion. It is for the conclusion of this question that the illusory substance was named the space-times. But it is not scientifically appropriate because modern science says that space-times are empty. But there comes the concept of another field instead of the ether field. First came the electromagnetic field. It was a temporary solution to the philosophical problem. Now Higgs has come up with a particle concept. That is, the Higgs concept exists as a metal medium for electrons. Higgs fills the entire universe. Modern science does not have a great understanding of the cycle of particles in the Higgs. But there is no particle concept in ether. The motion in the ether is Nadabrahma i.e. the concept of waves in the ether. So when it comes down to it, ether is just a matter of force. Mass expansion does not occur in force expansion. There is a problem in the particle concept of mass diffusion into small particles which modern science has not been able to prove and its cycle has not been found. Then what modern science discovered. Particle concept does not come in the case of radio waves. The particle concept comes when it enters light. All waves at a frequency higher than light conquered the particle concept. Gravity wave stands apart from the particle concept. An attempt is made to find a graviton particle in the gravitational wave. If the gravity particle is determined then the wave is not the particle. I do not know where all this is going. When the truth is deleted, it will come without knowing it. Modern science spacetime is a form of illusory matter. When gravity is visualized with a small wasp, gravity is analyzed by placing a medium there. But modern science insists that it must operate in a vacuum. But I do not know how to do that. It is very difficult for modern science. Earth's space time. Time requires space to move. The vast universe requires space for the greatest amount of time. But time does not move to infinity because the universe hits the limit and repeats itself infinitely as a cycle. The repetition of the universe is called fate. The Maspit Principle is a new theory that tells the cycle of the universe. That is, Maspit is a repetitive theory. Time is a universal repetition. It will take unimaginable number of Earth years to repeat this vast universe. I will post this post again on Facebook in the next iteration of the universe. Neither I nor the forces of the universe can make a difference in that. 1) First you need the circular space to fit. 2) The way the planet Earth should fit. 3) It must have a circular repetitive motion of the earth in such a way as to fit. 4) The Earth must rotate at a fixed speed. Light and dark make time beautiful. Universal time can be measured by time on Earth. As the whole world measures rain in centimeters. Each of the eight planets will have a spacetime. That is, a year on Jupiter is the sum of 12 years on Earth. That is the relativity of time.

[@angelmendez-rivera351]

@@kishorens2787 You said way too much nonsense that is just not accurate.

[@psycronizer]

@@angelmendez-rivera351 I agree, as soon as he said that modern science says space time is empty that was the first of many errors. Sorry Kishore, but you are wildly incorrect in your many "truths"

[@harley3514]

Love this series, thank you for a new episode!

[@No-jb6fy]

I'm not trained in the field, your stuff is challenging yet accessible, so thanks for that!

[@natedawww]

It seems to me, a non-physicist musician and composer, that a single particle's location in spacetime (its waveform) can become a bit "smooshy" relative to what's around its general vicinity, forming a bell-curve of probable locations as it extends outward (with the width of the bell (the "Q" value on an equalizer, in audio terms) being that "smooshiness"). In that case, my mind imagines that it merely co-exists inside and outside the barrier simultaneously (the whole Schrodinger's cat thing), with a lower probability of existing outside than inside. If that particle is forced to interact in some way (through observation or otherwise) and the waveform "collapses", then the probabilistic nature of the waveform can result, however unlikely, in the particle existing concretely outside of the barrier, even if it's the less likely event statistically. This to me suggests that it takes *no* time for it to travel across the barrier, but also that it didn't actually "travel" at all in the first place! It was just simply... there. The "travel" time, if you will, is more just the time it takes for the particle's location bell curve to widen beyond the end point of the barrier, and once that happens, it's no guarantee that it'll actually end up there. EDIT: More thoughts. In audio, a waveform has to have some width associated with it, since it takes time for the wave to oscillate. If it doesn't have a time value greater than t = 0, then the sound... doesn't exist. It's theoretical, but nothing is actually produced. You can tell a computer in principle to produce such a "sound", but the *actual* sound you would hear coming out of your speaker(s) would require it to take up time, as the speaker cone is forced to oscillate at some amplitude, however abruptly. As a corollary, it seems to me then that a particle's location *has to be* imprecise, the bell curve of its probable location has to have some width associated with it, however narrow, *in order for it to exist.* For to have 0 width would require there to be no slope (or I guess a vertical slope? But we all know where that leads), which means it *wouldn't actually exist* as a part of whatever field it's associated with...

[@TheRABIDdude]

Pretty sure all of this is correct

[@sweetdrreemz]

That's some genius way of describing things. Nice. Wish I had thought of it that way.. Makes sense to me..

[@angelmendez-rivera351]

As a physicist, this is all relatively accurate

[@TheRABIDdude]

​@@angelmendez-rivera351 As an English speaker, this is a dangling modifier.

[@angelmendez-rivera351]

@@TheRABIDdude ?

[@WWLinkMasterX]

Something tells me that the explanation for all this is going to be some "cheesing of the rules" in the same vein as quantum "teleporation." There, it is said "information" propagates faster than light, but can't be "unscrambled" without an informational "key" that must travel sub-luminaly. Trying to force the information to unscramble without the "key," results in random noise indistinguishable from having no transmitted signal at all. Likewise, there might be some fundamental sense in which ftl signals from tunneling can't be precisely determined to generated by the process, without some additional sub-luminal mechanism. It might be said then that the speed of light is not the fundamental limit at which physical phenomena can propagate, but at which information that definitively defines their states can propagate. The speed of information, or the speed at which things can be known.

[@HaloForgeUltra]

This makes no sense. Energy and light are information after all.

[@arpitdas4263]

Quite interesting

[@Mythreesons137.]

you sound very smart

[@chrissonofpear1384]

@@HaloForgeUltra Only spectrally or by polarization, maybe...

[@HaloForgeUltra]

@@chrissonofpear1384 What do you mean spectrally or by polarization? Spectral is literally just a method of collecting data, and polarization is just a changing of states, or a change in information.

[@afdallismen]

Somehow watching this video, make me fells like reading "universe changelog" as in software changelog, hoping there is new update to the physics of the universe.

[@mrpedrobraga]

Wish it never gets a new major update. Have you heard about Vacuum decay?

[@333STONE]

Want a better understanding look up Phil Langdon a physicist and much much more. One could say Its the single best decision One could make to figure out the One thing which is not a thing.

[@danielalorbi]

@@333STONE It's "nothing". Boring riddle.

[@aoabali]

udp ftl no permitted

[@hell5fire974]

Do you want Vacuum decay? Because that's how we get vacuum decay.

[@Erik-pu4mj]

Quite the on-topic distraction from studying for my intro to modern physics midterm tomorrow, which includes the SWE and finite square wells.

[@Alexandermhinton]

This channel represents best the1 hours spent on youtube for me. Thank you for all your work.

[@karlwaugh30]

It seems like single "quantum bits" of data could travel FTL, but that there is some statistical aspect of non-FTL and so the law of light speed becomes similar to things like the 2nd law of thermodynamics which is statical in nature. Does this make it stronger? Does it point to a relatively/QM cross over having some form of statistical nature?

[@Pika250]

reminds me of a pattern in Conway's game of life, I think it's called stargate, where a spaceship, I think was a lwss, entered the stargate and moved out as though it went faster than c, and another lwss just on its own was moving in tandem several pixels due south and in the same phase, and this lwss was here as the control -- a lwss moves at c/2 btw

[@intendedviewer922]

Happy once again that you have come through PBS

[@stapuft]

PLEASE, PLEASE, PLEASE, do a video on the "flexibility" of time, for example the "delayed double slit experiment", where the "observer" is so far away from the experiment that by the time they actually observe it, the experiment is long over, YET, the fact that they observed it STILL has an impact on the outcome of the experiment, even though it happens AFTER the results, instead of before/during, like in the normal double slit experiment.

[@markverheul9851]

My understanding is that ‘observing’ isn’t the correct term of this and that someone physically observing the outcomes of the experiment- no matter the time or distance from the experiment itself- is irrelevant. The wave function will collapse once the particle has to interact with something else. Wether observing it or not, the interaction has happened, so the function has collapsed.

[@herbivoretarleck4149]

Does a black hole event horizon qualify as one of those seemingly impenetrable barriers through which a quantum particle could tunnel?

[@dared29]

Hawking Radiation could possibly qualify as a particle that quantum tunnels through black holes. He mentions it in the hawking radiation video but says we'll never know until gravity and quantum physics have been united

[@spacemanspiff7283]

An event horizon isn’t actually a solid object, it just marks the no return point where nothing can ever exit the black hole. The actual mass is in the center in the singularity

[@richardsrichards2984]

@@spacemanspiff7283 no actually we dont know that

[@spacemanspiff7283]

@@richardsrichards2984 wdym? A black hole a point in space that has so much mass in it, it curves space time faster than light. As far as we know, the singularity at the “middle” of the black hole is where all the mass is.

[@backwashjoe7864]

@SpaceManSpiff The barriers that he talked about are not necessarily physical objects either. They can be something like a potential energy well, where the particle "shouldn't" have enough energy to overcome the barrier.

[@patrickmccurry1563]

I always figured that if FTL travel was at all possible no matter how absurdly difficult and carefully we create experiments, then it would have to happen by natural processes somewhere. That would lead to break downs in entropy and causality that we could observe.

[@falseprophet1024]

Why would it break down causality? Relativity relies on the speed of light being the speed of causality.. if thats wrong, then you cant get an answer from the now proven wrong theory..

[@royd4415]

Thank you so much for not being on of those and focused on knowledge thank you some or at least me me have been trying to figure things out without hateful judgments

[@cristiangedderth9576]

I understand nearly nothing from your videos but it makes me chill so i keep watching

[@StrayVagabond]

Can you force a particle to tunnel? Like, you have a particle bounding between 2 barriers, and you slowly bring those barriers together, eventually the space between them will grow smaller than the size of the particle itself. At that point will it tunnel, as it has no where else to go? And if it does, can you then set up an array of these small gaps where once it arrives in the next one, it would have to immediately tunnel again, and again, until it reached a place where it has enough room to exist?

[@-min-hw9qw]

Interesting question, you should start with looking into the Casimir effect - that's when you confine space so much that some quantum waves can't fit inside and you get a force pushing the 2 parallel plates even closer together.

[@ALIGHTFORTHEWORLD]

While not exactly this, I was wondering a similar concept. If we can at some point discern exactly what scenario or action is causing the tunneling effect to begin, could we then induce this manually ourselves?

[@danieljensen2626]

Pushing the barriers together would increase the energy of the particle, so it would be able to classically pass over the barrier (without tunneling) at some point before the gap closes to zero (at which point a particle still in the gap would have infinite energy).

[@apocalypseap]

and what if one of the barriers is bigger than the other? If the particle tunnels in that scenario, then it'd be very likely to tunnel on the thinner barrier's side, right?

[@shagster1970]

Thats exactly how a solid state hard drive works.

[@devinnall2284]

I wonder, has this ever happened in a particle accelerator? Instead of smashing into each other a 99% the speed of light one particles just teleports to the other side right as they're about to collide?

[@georgeparkins777]

It must happen all the time, right? Due to uncertainty it must be that every collision has only a chance of occuring

[@DoryenChin]

I bet it happens so often that they can’t even measure it because it would be indistinguishable from a miss

[@stephenchurch1784]

It happens in computer chips. The slowing in Moore's law in recent years is partially due to the fact that we can't pack transistors any closer without quantum tunneling becoming an issue. Research is being done on using quantum tunneling in the architecture of chips to get around this problem

[@kaitlyn__L]

@@DoryenChin cool icon! Is that vector art?

[@DoryenChin]

@@kaitlyn__L i'm not sure! i had it commissioned. 😅

[@craig_z]

I'm 10 mins in and I'm actually still following! This has to be a first for me with a PBS Space Time video on Quantum stuff.

[@bishwajitbhattacharjee-xm6xp]

A good topic , good presentation and a talented tutorial. You are truly doing justice to your name and expectations. The science of tunneling wierd by own right as long as wave function and it's characteristics​ property is our concern. Out of many good points in this new report I can see that wave function may not be electromagnetic in nature. Your SR prof. mostly centered around electromagnetic light. What if exponentially decay function leaks gives us an anamoly. Dirac's equation has given us particles of wierd properties . As the experiment have also seen a change in spin state. Thank you.

[@Dragrath1]

Interesting if this does indeed get confirmed to be unable to violate causality this may be able to greatly strengthen the case for distance being an emergent consequence of causality. If every particles wavefunction is really spread over all of space can anything really move at all except in relation to something say causal update propagating through a network? Regarding the monopole thing from last episode if they do in fact become black holes wouldn't you need to account for their antiparticle counterparts being unable to annihilate since a black hole doesn't care what originally collapsed to form the black hole. If the black holes formed from magnetic monopoles find and attract the black holes from their antimatter counterpart, wouldn't that erase the ability to tell the black hole from any other black hole?

[@ilovebutterstuff]

As far as space time goes, I personally would throw out light speed as part of the equation. I feel it's irrelevant. You seem to have touched on simulation theory, which may or may not present new problems. I had to go over the propagation of causality for a while, and have come to understand it as 7th dimensional (mental matter pertaining to consciousness) and utterly unpredictable, don't see how it would fit into travel. Black holes would be a consideration, because they do manipulate space time, but only in the frame of our particular physics, and our limited perception of the universe (extremely flawed). Even with the help of more advanced beings, I don't think our grasp is anywhere near sufficient. Newton's third law is the best we got as far as travel. Enjoyed your comment

[@Havicerxx]

I feel like distance being a consequence of causality just makes to much sence to not be true kinda like a ying and yang (I dont know how to spell it) but everything behaves in this manner, push and pull if you will also the concept of pulleies double the force on the rope with every pulley added simply by dividing the load into two directions

[@godamid4889]

Might explain spooky action at a distance?

[@danieljensen2626]

Distance being an emergent property of causality melts my brain too much to think about. But regarding the black holes, they are able to have electric charge so if magnetic monopoles exist they should be able to have magnetic charge as well. I'm not sure how relevant the antimatter thing is, yes merging black holes of opposite magnetic charge should cancel out the charge, but you can have that even just with regular "positive" and "negative" magnetic charge. Even adding in antimatter I think it's statistically unlikely that every such black hole would manage to exactly balance out.

[@PrzemyslawSliwinski]

@@godamid4889 My understanding is that "spooky action at a distance" describes instantaneous collapse of the whole wave function (of a single or of many particles - when the wave function is not separable).

[@joyboricua3721]

Brilliant! Also, Weasly became so proficient in muggle artifacts & tech, that he actually knew about the portkey tunneling phenomenon.

[@loturzelrestaurant]

9:30: Sounds like something that just some new invention humans ‚just’ dont have ‚yet’ would fix that and then allow FTL Travel to happen. We know the bridge is on flames, but the invention of fire-immunity-hazard-suits will totally fix this and allow everyone to cross the bridge; if you know what i mean.

[@Brandon-rc9vp]

Excellent as always, thank you so much!

[@roseproctor3177]

"The long way round" My little Whovian heart jumped :D

[@notdolandark]

One of these videos Matt should just where a shirt that matches the green/blue screen there using

[@randolphtimm6031]

So then all we'd see is his head bobbing around and his hands moving up and down?😁 What color are his eyes??

[@whoeveriam0iam14222]

scientist: I found a way to go faster than light everyone: ok now go look for your mistake

[@333STONE]

You are light

[@supermaster2012]

@@alexander-mauricemillamlae4567 the real light is an asian trying to pronounce right

[@kristoffervictorlorico1335]

Exactly why science is great

[@viniciusaraujoritzmann]

It's not just Quantum Tunneling that seems to allow faster than light communication, it is easy to show that entanglement also allows. There's a method that works in classic quantum mechanics and can't be denied by any theorem which is to send pairs of entangled polarized photons to two places A and B, B side can send information to A by measuring the polarization of the photons received in different angles, and the A side can receive the information by measuring how much light goes out by a side of a beam splitter, in which enters one of the photon-pairs and ancilla photons with known polarizations. Quantum Mechanics says the amount of light that goes out by the sides of the beam splitter depend on which angle the polarization of photons-pairs were measured by B. When I sent this to a journal they just said it was based on classic quantum mechanics and therefore should not be considered, but since there's ways to test it, I think it is very important to consider.

[@Ncaa67]

So consider this, The beginning of the universe starts with nothing, the universe has the “I am” moment where the fist snap of energy comes into being. There are no reference points no speed limit and no time so any movement traveling goes back in time( by our perspective) to fill the void in the past. Like a wave in a multidimensional lake it disturbs the void . But that snap is also going into the future, as the past is created it also travels to the future from the past and the overlapping waves are the present and as the past is created into infinity the resulting buildup in the present creation becomes so dense (E=Mc^2)that mater is formed and the universe becomes infinitely dense. Gravity is the flow of time into the past. A black hole is just the accumulation of matter which is made up of pieces of the first realization of the present which we interpreted as the “Big Bang” and the moment when “all matter?” In the universe is created which is really made up of black and white hole quantum looped waves. So when we see things like quantum tunneling, and quantum weirdness that seem to move faster than light and have missing information( mass or energy) that is movement though the quantum wormhole that matter is made of. The random events we see are because of the way we are looking at them not the events themselves. Currently we cannot see the actual travel through the quantum black hole through the wormhole and back out the invisible past of the white hole. We can only see the accumulated effects resulting in quantum tunneling, gravity, time and matter, for that matter 😂

[@sum_rye_hash_321]

"Because wizards are rubbish at quantum mechanics" That is now canon.

[@davidh8367]

That statement seems to be based on a number of assumptions and a few biases

[@magearamil8626]

Time stamp please!

[@drjonez1]

@@magearamil8626 17.08

[@CovertGhoul]

SKD

[@Hack3r91]

I'm having a bit of trouble with the "slower than light signaling" caveat with these newer results. Faster than light signaling seems to be unlikely, rather than impossible, whereas according to other experiments and theoretical analysis, it appears to be a hard limit. Did I get anything wrong?

[@southern-samurai]

This channel is really beyond my understanding most of the time, but yet I’m subscribed and drawn to the videos..

[@fritzzz1372]

loving the double description

[@D3ADmanWA1KING187]

When you are sending your message via tunneling particles to your friend, is it technically possible (Albeit extremely unlikely) for all of the particles to tunnel on the first go rather than be reflected? If so, could the return message not also do the same thing? That would then result in faster than light information being extremely unlikely to occur, but not impossible.

[@mythicdawn9574]

That's what I thought of the answer from the paper. If it's actually just what Matt said, then it looks more like "we don't want to make clickbait claims so we evade the question". If their answer to causality paradox is just probability based, then there is no reason those events, how improbable they may seem, would not occur at some point. So there might be an additional physics rule we don't know yet, or a "probability rule", something like "probability in this universe is quantized, so anything mathematically bellow a certain probability is physically transcribed as 0%". Or time travel exists. :p

[@CellstageCards]

First I thought, "Can I increase the transmission rate by vibrating or heating the barrier. " Then I saw that this has been studied. Now I wonder if increased transmission rates have faster or slower speeds (ie. does helping the transmission slow it down at all?).

[@lepidoptera9337]

All you are doing is increasing the noise. Noise is not information and correlation between two noise sources is not causality.

[@JohnDlugosz]

The barrier is not a wall like bricks. It is a potential well, an energy level trapping the particle.

[@AFMR0420]

If the barrier is energy then it is traveling in a wave function, and the particle may just be slipping through a trough.

[@lepidoptera9337]

@@AFMR0420 The barrier is an energy barrier and the particle is not actually a particle. It's a quantum of energy. So you are really debating the difference between energy and energy when you are talking about a potential well problem. That difference doesn't exist, of course. It's like trying to keep water out of your house with a wall of water.

[@bloodyorphan]

Great vid bud :-) 10/10 in my book. There is more than one type of quantum tunnel, you are describing the first which will heat up the teleport medium because of the energy required to punch through the 3d space skin leaving a small wormhole in the skin which exhibits more BB space expression in the atomic structure. This tunnel attenuates signal and is good for signal noise suppression. I speculate the other quantum tunnel (I.E. Teleportation), translates the 3d space skin magnetic apertures using a Newtons cradle effect through the BB special relativity weight space of the transmitted particle/structure.

[@Gorlokki]

It's 4am, I can't sleep and I'm super pumped watching this :)

[@acetate909]

Elon Musk should create _The Neils Bohring Company_ and do some quantum tunneling.

[@TO-ll4js]

What neihls are gonna hold up it up?

[@DrakiniteOfficial]

That was a really good one

[@Feefa99]

I am currently in superposition what I should write about that

[@mayusolanki3121]

LOL 😂😂

[@trajtemberg]

Dad, staph.

[@Twinfire0]

In the barrier vs no-barrier experiment, there will be multiple particles measured on the end of the beam's path with some calculated velocity distribution. I have a hunch that the absolute quantity of "fast" particles measured in the no-barrier experiment is almost always going to be higher than that of the barrier experiment, assuming the same number of emitted particles. It seems like the quantum barrier simply acts as a "filter" which favors faster particles (which makes intuitive sense, one should think that a brick wall only allows fast things to pass through, like bullets instead of basketballs).

[@KingofArsenal]

And anytime we find shortcuts , the universe takes them away though *ROLLLL CREDITTTSSS* SPACE TIME! that was just so beautifully put! I am finally glad to say that I am actually starting to fully grasp everything in this video, and all of it intuitively made sense to me. Thank you for ALL of the content provided by this channel, its beyond words what you guys have created here.

[@tankedwarthog6424]

I love the answer to the last question. It just boiled down to no I am a bigger nerd than you are.

[@SeraphRyan]

To me, this sounds like "subspace communication" from star trek, where they could talk to earth from almost anywhere without a time delay. But that only happens once the connection is established or something.

[@michaelyuhanek6628]

I was thinking the same thing.

[@parthsarda2793]

To answer this question that would quantum tunneling be travelling faster than light, you first need to define time in the quantum scale. Time is a weird property that we feel differently than the rest of the universe.

[@XEinstein]

Indeed! Time is only an emergent property from the entropy of a whole bunch of particles interacting. So for particles tunneling through barriers one really has to wonder if time exists at all in the process

[@ezimm1829]

@@XEinstein This is a tangent but it's a question I've had for a long time and you seem to know this stuff pretty well. The second law of thermodynamics basically says that entropy never decreases over time in a closed system. But isn't it also true that the reason we view the arrow of time in the direction we do is because of entropy increasing within our brains and creating information? So is entropy forced to increase as time increases, or is the arrow of time defined by increasing entropy? Sorry if the wording is weird, I'm a high school junior trying to understand complex processes, and also you kind of answered it already but just more as a clarification.

[@XEinstein]

@@ezimm1829 good question! Entropy is very strongly correlated to information. In fact, there is such a thing as information entropy, so yes for sure in your brain entropy increases as it processes information. The crux of the second law though lies in the 'closed system' bit. Biological entities like human bodies are not closed systems and therefore biology is capable of stopping the collection of atoms that make up bodies to have ever increasing entropy. A body is actually reversing entropy as it is a orderly system. As for entropy and time: time doesn't really exist and entropy seems to be a very fundamental property of physics. Look at it this way: the only way you experience time is because you see a cup of tea cooling off or a banana rotting. But now imagine an electron flying through empty space for millions of years without meeting any other particle. This means the electron never interacts with anything so how can you observe time from the behaviour of that electron. You can't because there is no process happening and so no time emerging. When it comes to emergent properties: think of temperature. Put your finger in a cup of water and you can feel the temperature, but look at individual water molecules then they don't have a property in them that we can identify as temperature. Its only when billions of water molecules interact in a cup that we can measure those interactions as temperature. So temperature emerges from countless of particles interacting.

[@ezimm1829]

@@XEinstein That will probably take a few read throughs to make sense but what from what I've read that makes sense. Thank you!

[@XEinstein]

@@ezimm1829 don't worry mate. I'm 41 years old and got very interested in physics when I was a junior in high school. At that time I has never even heard about the 2nd law, let alone entropy. And at that time we don't not have KZbin yet, in fact, Internet hadn't even been invented yet when I was a junior. Studying about thermodynamics came when I was studying physics at university. That's also when I started to learn about quantum mechanics and to this day I am learning. Its only recently that I started to understand how entropy, time and emergent properties work. So you have a full 20 years ahead of you to get your head around all things interesting in modern physic and with these questions you are well on your way!

[@solidaritytime3650]

Similar is when you approach the wall, and Flash into the center of it in League. The collision detection won't allow you in the wall, so you're pushed to the other side. This allows you to move further in the same period of time, than you'd have been capable of in the absence of a barrier.

[@debray-kingbomatthieu5579]

Quantum tunneling is near the behavior of quantum entanglement. The particule passes the wall of required energy, and goes the other side, at

[@benbooth2783]

I never thought of tunnelling as motion in a classical sense. I always understood it as when you look at QM potential well, classically you would expect to see all of the particles in the well, but in the QM case, out of all of the infinite classical positions that make up the superposition of a particle, some of them are outside the well, so when you look at it there is a chance some of the particles are outside the well. There is no sense in which the particle moved through the barrier, there weren't any particles until you looked at it and collapsed the wave function, and some of the particles coalesced outside the well. Have I got this wrong?

[@Moley1Moleo]

I think you're mostly wrong. Consider a radiation decay where a particle is ejected from an atom. It is sensible to say that the particle left the atom, and so the idea of motion seems relevant here. The particle was ejected from the uranium atom. This is motion. We could think of it as a wave instead, but even then the wave is moving, because the wave was emanating outwards and gradually leaking across the universe, travelling outwards from the atom. That is, I think that when the atom was formed, the wavefunction of this particle was mostly in the atom, and arguably spread out across the whole universe very thinly, but as time passes that wavefunction gets less concentrated inside the atom, and more concentrated in the rest of the universe. The particle's wavefunction leaks out of the atomic, and eventually it is observed outside. The wave is moving out of the middle of the atom and into the universe, and if you measure the particle you might measure it where you find some of the wave, most likely with velocity away from the source, a velocity you can measure, and if you know where the source is, you could deduce how long it has been moving. ----- But maybe I'm mistaken above. Even so, I think the specific case of consider sending a message with light is in favor of the concept of motion. You create the signal, and from then on there is a clear sense of motion from the source outwards (and perhaps to the receiver. Putting barriers (like a giant lead wall that classically I think would reflect or absorb the light wave) interrupts this motion, and a signal that arrives due to quantum tunneling clearly moved from the source to the receiver.

[@isitsaturdayalready1247]

@@Moley1Moleo I think you're the one who's actually wrong. @Ben Booth described it the way I understand it. The main problem with your description is that particles don't behave as we think particles would. They're all packets of energy within their quantum fields, and those packets are waves. The classical model of the atom with electron orbiting the nucleus is insufficient on subatomic scale. You can look up the potential electron locations for various atoms; it's not actually a ball flying around a groups of balls, but it's a probabilistic position around a fuzzy positive potential well. The same thing applies to the particles in the nucleus - they're just composed of waves with some probabilistic distribution of location and momentum. They are represented as waves as Ben described, and the idea is that a part of the wave extends beyond the nucleus, where the strong nuclear force is too weak, which allows the particle to escape. The strong nuclear force is what holds the nucleus together, and that defines the walls of the potential well as depicted in the video. A thing to consider, or where your explanation really comes short: the Heisenberg uncertainty principle. You cannot measure the velocity or location of the particle precisely (and certainly not both at the same time), and so you cannot reason about where exactly the particle came from, what speed it's traveling, and how long it took it; those things make sense only at scales above the atomic scale. That's why in the experiment in the video they had to use a different way of measuring time - a property that the particles carry themselves.

[@isitsaturdayalready1247]

@Ben Booth I think you get it right, and you can see my response to Moleo. :)

[@Moley1Moleo]

​@@isitsaturdayalready1247 - > particles don't behave as we think particles would. They're all packets of energy within their quantum fields >They are represented as waves True, but not the whole truth. Wave-particle duality means both apply. In a sense, there are perhaps no "particles" and there are no "waves", and both of those are just models. Instead, there only exist objects that are a genuine mix of both, and the situation changes how these objects interact, and often they behave in ways related to (but not exactly like) one of those two models. - >You cannot measure the velocity or location of the particle precisely Correct. We are not certain of exactly the direction and position, however we can still measure both to some finite precision. We're always off by some fraction, but overall the lower limit of the uncertainty product is quite small, so we can in fact measure the momentum and position, just with some uncertainty, and hence some uncertainty in whatever deduction we make with those measurements.

[@nicholasmaddalena1451]

I see the similarities in tunneling and quantum nonlocality

[@RexYoung206]

Tunneling time, proper time, phase space, etc.: I wish PBS ST had a quick visual guide/checklist of such terms from astrophysics, quantum mechanics, etc. So you could glance at an image, and see a full list & brief description of such esoteric terms. :)

[@stephanieparker1250]

Thank you, Matt!! 🙌💜

[@FalconFetus8]

Prediction: once they start measuring the speed of the particles using the spin method, they're going to find that they all stop moving faster than light. Then when they stop measuring the spin, they'll start moving faster than light again. Why do I predict this? Because quantum physics just _loves_ to mess with us like this.

[@dudono1744]

It has a chance to cease to exist tho

[@gristlevonraben]

So true

[@jasonsampson3379]

@Mike Fuller Regarding wave equations, the quantum scale (individual particles) differs only in probability. The position of anything, no matter the size, can be represented by a wave equation showing the probability distribution of possible positions. However, once the object becomes larger than at most a large molecule, the probability distribution becomes so concentrated that the position is effectively not probabilistic for almost all purposes. Technically, the sun could quantum tunnel to the other side of the Milky Way, leaving humanity to freeze to death, but the probability is so low that it may as well be impossible.

[@infinitemonkey917]

@@jasonsampson3379 So a giant organism with the same proportion to the sun as a human to an electron would experience stars the way we do quantum particles ?

[@ac.creations]

@Mike Fuller Its like expecting pieces of a clock to each tell you the time. Its fundamentally an underlying property of the pieces that make up our experience. The reality we exist in is a product of countless particle interactions that have entangled and traveled since the big bang.

[@briandoe5746]

So when are you going to do an episode on the cosmic ray that affected the Mario 64 speedrun in tick tock clock. It is now being reported that a glitch that has had Mario 64 speedrunners searching code and doing hundreds if not thousands of hours of research happened because of a cosmic ray flipping information stored in a Nintendo 64. I think it would be an awesome episode that could easily link into the backup systems we use for satellites and space probes

[@Kvltklassik]

Hope you're in good health Matt. Love from Brisbane.

[@josecartin825]

This was as interesting as incomprehensible, lol. The graphics and animations HELPED A LOT, made it clearer, please continue using animations (use and abuse when possible). Perhaps third time is the charm 🙂. Thanks for explaining this amazing topic @pbs

[@neeneko]

Something I am trying to understand : does the barrier even play much of a role? If what we are talking about is a wave function with a high probability of being in range A-B that are on one side of a barrier, and C->inf on the other side, other than making A-B more probable and C->inf less, if the barrier was not there we would still have some probability that it is in A-B vs C-inf, and so it could still 'tunnel' through free space from the centre A-B to whereever it was measured. no?

[@OuroborosVengeance]

I think the same as you. Maybe the barrier's only "job" is to tweak the probability distribution in the wave (i guess that that would look like stretching the function?). Im wondering what happens if the barrier is extremely thick, but i assume such a case doesnt end up ocurring irl

[@DFPercush]

I suspect it's more like a filter that lets you know, if you see anything at all, it had to tunnel through.

[@MrSigmaSharp]

Let's say the chance of tunnelling a particular barrier is 1% what if Alice fires 1000 particles simultaneously to Bob on the other side and Bob upon receiving sends 1000 particles back through the barrier. This way Alice and Bob can communicate faster than no barrier scenario (light speed). Or not?

[@Roust7]

Quantum eraser experiment can be used and has shown to break casualty. Second, the entangled photons sister pair can be separated going to person sending the signal but the other sister photon goes through double slit to person receiving message faster than light and message going back in time. You can use it as binary detect showing lines versus non detect showing interference wave as the signal going back in time.

[@clementvanhecke2832]

Great video as always, thanks a lot ! How do we know the particles actually passed the barrier and does not come from "somewhere" else, in a world where there is no barrier ?

[@Geraduss]

This sounds like some building foundation for the hyperspace traveling theory, as the space of the "barrier" could be just such a space.

[@kidddogbites]

wouldn't an Everettian universe solve time paradoxes? you wouldn't be altering a past timeline, rather exploring a different branch of the wave function.

[@lepidoptera9337]

No. You are welcome.

[@kidddogbites]

@@lepidoptera9337 mind explaining why?

[@lepidoptera9337]

@@kidddogbites For one thing because the wave function is not even a physical quantity. It's the equivalent of a probability distribution. It describes what would happen statistically if you could repeat the same physical experiment an infinite number of times. I suppose you are not Dr. Strange, so you can't actually repeat the universe an infinite number of times, can you?

[@kidddogbites]

@@lepidoptera9337 i guess that would depends on the size of and how many degrees of freedom are in the larger hilbert space, is it infinite? or just arbitrarily large?

[@lepidoptera9337]

@@kidddogbites No, it doesn't. If you want to have a probability distribution instead of just a frequency estimate, then you need an infinite number of throws of dice, already. Same for quantum systems. Half of the mystery of quantum physics comes from the trivial fact that people can't distinguish between an individual experiment and an ensemble. That's not a problem with QM, but a problem with people's minds. They are just not very good on average. :-)

[@TomasVolley]

Excellent, as always.

[@TheRABIDdude]

9:05, "Not so fast", hahahaha I see what you did there

[@shadowoftime3627]

When you talk about the barriers, have they tried different materials to see if certain barriers allow the particle to tunnel more often? Also one thing that I just thought of was, is there a way to pressurize a gas enough to make it act as a barrier just enough to cause it to tunnel but not enough to stop the particle from going through?

[@ananousous]

Sometimes, I feel ready to sleep---quite often actually

[@RS-zv9ip]

You should watch Action labs video on quantum tunneling

[@swordarmstudios6052]

Imagine a very long wire, made of extremely thin 'barriers' that could trigger tunneling, and voids where you could tunnel into. Now imagine that this wire was connected to two boxes, one that outputs a steady signal at a steady rate, say 1 particle per nano-second or something absurd. Each box would have a synchronized atomic clock, so it would know if particles didn't make it through the barrier. Now imagine an algorithm that encode arbitrary data to sufficient level that the average level of noise due to particles failing to pierce the barrier, wouldn't impact the data being sent. Essentially I'm asking is would it be possible chain many quantum jumps together deliberately to create a faster-than-light signaling mechanism based on this effect? A 'Hartman Wire' basically. So other questions about this ... how thin can a barrier be and still be considered a barrier? Seems like the threshold between barrier and non-barrier is pretty important to answering this question. Just asking probing questions, because this is a fascinating topic, and I'm a layperson without any training in physics but I'm deeply interested in the topic.

[@garethdean6382]

The issue would be getting the wire to send information at all. The chance of a single particle making it through all the barriers in the wire rapidly becomes essentially zero over any macroscopic distance which will in itself render the wire about as useful as waiting for all your atoms to randomly tunnel to New York for a vacation. Another issue is that unless you leave a large gap between particles those trapped in the wire may be overtaken or interfere with newly added particles which will either scramble your data or make the transmission rate incredibly low.

[@josephthompson5941]

Hartman makes perfect sense! How many cannonballs would you have to impact a mountain with to cause an avalanche on the other side? That's amazing. Thanks guys!

[@t.c.bramblett617]

One thing I automatically assume when on the quantum scale is... don't ask questions. I'm glad that extremely smart physicians have been pushing that boundary, though. Keep at it!

[@frans_duxin]

I feel like we’re getting closer and closer to FTL travel. Only a matter of time.

[@chloeirnes]

And space!

[@peterkelley6344]

♬♬ All in a matter of time? Genesis?

[@felipesantiago4271]

Only a matter of spacetime!

[@TransRoofKorean]

My gut, which seems to work better than my brain in these matters, says that quantum tunneling is literally instantaneous, in a way that would confuse even relativity. There are a lot of ways our current physics models are confused because they're inaccurate, depending on almost-wrong ideas, and this is one. If somehow tomorrow I were proven wrong, it would make me question reality itself. Speaking of which... actually, the more time goes on, the more I think it makes sense to _imagine,_ actually *_assume,_* the world we know is a computer simulation. Everything quantum makes *infinitely* more sense that way.

[@pabloquijadasalazar7507]

Hey I’ve been pondering this question: does light even move? Or is everything else moving, and the speed of light is just how fast everything else can move? Like, we’re all made of matter, and matter moves, but spacetime & light don’t. Matter moving disrupts both spacetime & light, thus matter experiences resistance as it moves through, causing the phenomena we experience as physics & everything else. Is there some physics or another video I can watch for that?

[@wordysmithsonism8767]

A great one! Thank you!

[@user-qz6tg7wd8i]

"As the barrier gets thicker, exponentially more get reflected until only an minuscule amount pass through" Isn't that mitigated by sending enough particles that detectable amount of them passes?

[@CrazyGaming-ig6qq]

Logically it would. The problem is that the amount that are reflected increases exponentially; you very quickly needs to start sending enormous amount of particles.

[@Woffenhorst]

At some point, the amount of particles you would need to send would just cause a black hole to materialize.

[@lexlee2211]

While it would seem faster to move the boat across the ocean, moving the ocean across the boat would mean you wouldn't require a boat

[@tim40gabby25]

May I suggest a drone view of a Marathon field as an analogy, with regard to attempting to define the finishing time of one runner by examining the times of all? .. with a couple giving up and returning to the start. Just a thought.

[@EebstertheGreat]

This reminds me of nonlinear crystals in classical optics that can allow the phase and group velocities of light to take on any real value, even though the precursor always travels at exactly c.

[@denysvlasenko1865]

Quite different. For example, phase velocity of any massive particle (e.g. electron) wavefunction is ALWAYS faster than light, and tends to infinity as particle slows down. IOW: superluminal phase velocity is completely mundane.

[@EebstertheGreat]

@@denysvlasenko1865 IDK, a refractive index between 0 and 1 isn't that strange, but a negative refractive index is very strange. And a group velocity >c was once thought to be impossible.

[@christopherrseay3148]

this channel is so high level that even my master's in astronomy isn't always enough to watch a video once and grasp it. love it!! thanks matt, and pbs. :)

[@SherryDC]

I don't think there is a single individuum who actually is able to grasp quantum mechanics. It's more like a collective understanding, getting more and more precise by theoretical and experimental physics until someone can write down a theory that combines what we observe with the math behind. The next Einstein if you want (and even he didn't fully grasp special relativity nor quantum mechanics).

[@osmosisjones4912]

Maybe we can't hear signals from aliens to other aliens. Because they use Quantum entanglement for phone calls . Seti is like. A tribe on an island trying see if anyone else is on other islands using smoke signals. With rule its never what were looking for . And few other island have cell phones and wind ruins any messages from. Those who do use smoke . And their natural explainations for Smoke

[@cherubin7th]

Could also be an artifact of how we wrote the equations or how we model tunneling.

[@brucepaterson6961]

It is said elsewhere that evanescent waves are the classical equivalent of quantum tunneling and there is a very easy experiment to do that at first look seems to show superluminal wave propagation. Send a wave down a waveguide at a frequency just below cutoff. Measure the phase velocity - it seems to be propagating much faster than light. But that is only for a constant single frequency signal which caries no information. Then try modulating the wave (so it caries information) and hay presto, the group velocity is much less than the velocity of light. It looks like quantum tunneling shows the same behavior.

[@w0tch]

It’s very often repeated than FTL movement implies being able to time travel but I think it’s really an unfortunate interpretation of the spacetime diagrams of special relativity.

[@danilooliveira6580]

I think its more like an interpretation that FTL breaks causality. but if no causality is broken, then does the travel time even matter ?

[@DFPercush]

Yeah I don't know about the whole time travel paradox thing. It could only affect how a distant observer perceives history. It's not like you can go back and change your own past where it actually happened. If I hop on the USS Enterprise and warp over to Alpha Centauri and back, I wouldn't arrive 8 years in the past. Although 4 years later, you'd see me over there even though I'm on Earth again.

[@mythicdawn9574]

@@DFPercush I'm no physicist (although I have a scientific background), but I always considered time as something that is already (at least partially) written, at least that's my fav theory as a non expert who has no clue how the math works. I don't see how information moving backward in time would be an issue. If it respects some rules (no randomness, for example), it just creates time loops. Time loops are only an issue if you consider that space-time is constantly written as time flows forward, because when you encounter the most ancient part of a time loop, the causality is violated. But if time was already written entirely from the big-bang, be it fully deterministic (every "randomness" of quantum physics is actually a rule we don't understand) or multiverse-deterministic (universes emerging from every random quantum event are all already written, and current random events just make our reality "navigate" between the various universes, like a choice-based video game), then time-loops were already "created" when the verse was created itself, and us humans are just subject to the illusion of time through the "arrow of time", which may be a different phenomenon from time itself (just like space is not the same thing as space dilation). But if time loops actually exist, then they might be very rare, very small and hard to detect, or both. Else, we would already have examples of causality being broken. Here goes my fun "theory", against all odds :p

[@denysvlasenko1865]

@@DFPercush > It's not like you can go back and change your own past where it actually happened. Incorrect. With FTL, you can do exactly that. A location reachable only with FTL, in suitably selected boosted coordinate frame, is literally in the past. Then, from that location, FTL travel back can return you to the place you started from, but in its past.

[@goldnutter412]

Space is just data, why calculate where anything microscopic is until you measure it

[@Adalast]

How does one become an animator for Space Time? I would love to work with you guys.

[@daikyraraga8382]

They only recruit people able to quantum tunnel right inside the studio

[@paaao]

If you want to send a message using sound, and you choose empty space, your message will definitely be slower than sending through piles of rocks or other materials. ("Barriers") In fact, even sending sound waves through open atmosphere here on Earth is slower than transmitting the same sound waves through the upper layers of the Earth's crust.

[@JoseCastillo-wx6jd]

Excelent video, thank you.

[@spudd86]

Why does thermal energy affect all fields? I don't really follow the connection between temperature as the average kinetic energy of particles and things like the Higgs field and strong/weak nuclear forces.

[@EvilSpaceHamster]

Stupid Question: How does a barrier make a difference? Can the particles not tunnel through so-called empty space? What phenomena causes a barrier to affect the wave function? Surely the barriers, like most matter, exists mostly as empty space?

[@jdrake1428]

Quantum tunneling arises from the idea that a particle can exist *within* a potential barrier that is greater than it's kinetic energy. The barrier itself changes the functional form of the wavefunction, so it is different than a wavefunction is free space. (That said, the concept of tunneling time doesn't make sense in a strictly QM interpretation.)

[@drdca8263]

the barrier needn't be "made of stuff". The "potential barrier" is a region in which the potential energy is higher. For example, if there is a region with a negative electric charge (due to having many negatively charged ions there, for example), then e.g. an election would have a higher potential energy in that region. That's the kind of potential barrier in question. It may be there *because* there is some stuff there, but the potential barrier isn't the same thing as the physical barrier.

[@EvilSpaceHamster]

@@drdca8263 That makes sense! I guess as a layman, I have to forgo the classical interpretation of 'stuff' and think about fields?

[@frede1905]

It's not necessarily a physical barrier, but instead a potential barrier. ie. a region of space where the potential energy is bigger than the particle's total energy. In classical physics, a particle can't exist in such a region, let alone pass through it. This is because "total energy" is just KE+PE, and since KE >0, you get that the total energy must be > PE. In QM, where the energies become operators, you don't necessarily get that restriction.

[@bergh070]

The animations are really cool!! Shout-out to the animations team!

[@roshanrajprasad]

Want to hear wow signal - kzbin.info/www/bejne/jZbPlnqils50jMU

[@onderozenc4470]

Superluminal velocities are possible if some frequencies in vacuum fluctuations coincide with that of the electromagnetic wave (at Ghz frequencies)..