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Quantum Entanglement and the 2022 Nobel Prize in Physics - Sixty Symbols
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- čas přidán 10. 10. 2022
- Some of the Sixty Symbols Professors discuss the 2022 Nobel Prize in Physics.
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Featuring Phil Moriarty, Mike Merrifield, Ed Copeland, and Tony Padilla - all from the University of Nottingham's School of Physics.
More of our Nobel Prize videos: bit.ly/SSNobel
A bit extra from Ed Copeland from this interview: • Hidden Variables (extr...
The Nobel Prize was awarded to Alain Aspect, John F. Clauser and Anton Zeilinger "for experiments with entangled photons, establishing the violation of Bell inequalities and pioneering quantum information science".
More at: www.nobelprize...
See our video on Bell's Inequality with Mike Merrifield: • Spooky Action at a Dis...
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It's such an injustice that Bell could never have been awarded it. After all, it is the No Bell Prize.
That's also the reason why Jocelyn Bell never received the prize.
Brady's various post-Nobel-Prize videos are the highlight of my year, and the coincidental release of the incredibly excellent "Spooky Action" video is just bananas. Today is fantastic.
Yeah the fact that it is so coincidental is a bit of its own spooky action at a distance.
@@CalvinHikes co incidents be like that
Talking about spooky, Sabine Hossenfelder got it right 1 year ago!
Brady's channels are a thousand times better than the rest of CZcams. He should get a knighthood at some point.
It was pre-determined... 😉
Sounds exactly like what someone who fixes horse races would say .
🤣
I'd like to hear more about the "...at least locally." aspect in another video. Two of the speakers mentioned this.
It means "excluding any external influence on the experiment". The system is statistic, but that may change if there is some external influence.
@@framegrace1 That's incorrect, as I understand it. Locally means no "spooky action at a distance." Hidden variable theories can satisfy Bell's inequality if they allow for non-local action, i.e. if they allow for "spooky action at a distance." At least, that's what I've picked up from many other videos I've seen on the topic.
They are referring to the fact that Bell’s inequality disproves hidden variable theories that are local. They stress “at least locally” because a global hidden variable theory is still a valid explanation
Locality can be saved with the Many World interruption, which suggests that all possible outcomes happen, but only outcomes which are consistent (or in phase with one another) will continue to interact with one another. But this removes realism since there's no longer a single shared universe.
Realism can be saved with Pilot Wave interruption, which suggests that things like super positions aren't real, but are the result of a shared hidden variable.
Local Realism can be saved with Super Determinism, which attacks the statistical independence of measurements made. Basically saying that the only measurements which can be done, are the ones which create this correlation. Most physicist have major objections to Super Determinism, as it requires almost conspiracy level thinking to think that universe would work this way. But there are serious and adamant defenders of this hypothesis.
“local” just means “lightspeed or slower”
Love watching clever passionate people talk about inspiring achievements. Makes me want to change my profession and take up Physics
I work as an engineer and this really makes me wanna go back to university and get a physics degree :D
Bell's test just disprove local hidden variables with statical independence. Bell himself was a believer in Bohmian mechanics.
We NEED to talk more about superdeterminism and non local hidden variables. This nobel prize isn't the end of the story.
"Probabilistic" just means that there are still unknown factors that are having effects that we are not understanding and not predicting. It just means that we are still not seeing things with enough "resolution", meaning that these things that you believe are the fundamental building blocks are still not the base level of construction of reality and there is yet another layer of construction below sub atomic particles that are actually constructing the sub atomic particles themselves.
Its easier to think of it on a higher scale as an analogy: If you were to look at any one molecule of gas in the atmosphere and try to predict exactly what it is going to do next or even project it into the future, your answers would be very probabilistic; because there are local factors, there is the influence from all the other gas in the atmosphere, there is the gravitation of the Moon, there is even the heat from the sun while on the other side of the Earth, etc: that all have effects on what any one molecule in the atmosphere does, and that's why predicting the weather is so difficult past a given stretch of time. There is "probability stacking" (aka tolerance stacking in the machining world), where there are too many possibilities happening, one after the other, for the 'reaction chain" to every be predictable. But at the same time, we still understand that what is happening in the atmosphere at the molecular level is very deterministic. Everything has a cause and effect and it is all interacting in a very predictable way, but with unpredictable outcomes due to the probability stacking. I believe it's possible that this same sort of thing is happening in these experiments; that there are far more complex things happening below the surface, and all that we are even able to see are the effects, but not the actual causes.
Just imagine I'm standing in a dark room with a ball on a string and I'm swinging it over my head, and maybe if you add heat I'll spin it faster, or cool the room and I'll spin it a little slower at times, maybe I swing that ball left and right or towards the floor, anywhere I want to. If you were to snap a photo in the dark -- you would see me swinging this ball around, but you could never know where that ball was going to be until you look. This is the "probability" that you speak of -- it's simply us being in the dark about certain parts of reality. You could continue to snap pictures in that dark room, some times the ball would be to my left and sometimes to my right, etc.. so you could say that it's actually everywhere in that room at once, until you snap that picture and know for sure. But to us it's a very simple situation, because we know that I'm just a person standing in the dark swinging the ball around -- so we can make sense of the pictures. When you're looking at photons or even sub atomic particles, you have no idea what is really going on in that dark room--- all you can see are the snapshots and their probabilities; but this says nothing to what is actually going on in that dark room of reality.
Agree completely
@@calholli No, it's not about resolution. Bell's Inequalities literally defines a way to test between results produced by a truly random probability distribution, or one produced by unknown Hidden Variables that we cannot see or find yet.
An experiment proving Quantum Mechanics using Bell's Inequalities disproves the existence of any resolution problems or information problems being involved in a fundamental randomness.
Unless the Hidden Variables can update with regard to information recieved faster than light (since Bell's Theorem assumes that isn't possible).
It's worth noting that there are still physicists out there who have doubts that QM is complete, perhaps most notably Lee Smolin. Bell's Inequality has some assumptions regarding the initial state of the system, which if untrue, leave the door open for the possibility of hidden variable theories.
That being said, the work of these three physicists undoubtedly advanced the field and merits the Nobel Prize.
amazing that question of assumptions was seemingly not asked/addressed
@@TheDirge69 Some of the assumptions are rather weird, such as measurement contextuality, so it is not unlikely that most physicists disregard it.
Bell's Inequality and other so called "no go theorems" are rejected by almost all physicists except those making Pop Sci hype videos on CZcams. Gell-Man rejected it, t'Hooft, Hartle, Omnes, Griffiths, Streater all reject it. It was pointed out by Itamar Pitowsky in the 80s that Bell's Inequality is just a restatement of Boole's Inequality in Probability Theory and only holds if one assumes that all observables involved are defined on a common probability space - which we in fact know upfront not to be the case, so there is absolutely nothing meaningful or surprising about electron spins not obeying it. It tells us nothing about realism vs non-realism as realism is not a required assumption to derive it - already pointed out by Eberhard in the 70s. It tells us nothing about locality vs non-locality as locality is a redundent assumption, pointed out my many including Pitowsky, Fine, Streater, Philipp, Hess and many others beginning in the 80s. If one assumes a joint probablity space (or a classical state space that implies such) then BI will hold and throwing in nonsense like non-realism and or non-locality does not change that fact and such mechanisms cannot be used to explain why electron spins disobey BI. Accepting that not all probability distributions can be represented as marginals of a single joint distribution (a purely mathematical fact having nothing to do with physics) does explain it.
Yep. People like Nima Arkani-Hamid at Princeton put forth pretty convincing arguments that QM+GR are emergent, and nothing gets broken re: locality or unitarity("space time is doomed"). "Every time in science we've had a conflict of two fundamentally well established concepts, there has been some emerging new science from which these concepts emerged." Lenny Susskind out of Stanford basically agrees with this re - "Conflicts of Principes".
@@NuclearCraftMod If you are referring to those who reject critiques of Bell et al because they think contextuality is weird, then such people have a deficient understanding of formal mathematical probability. Dependency of measures (in the sense of measure theory and probability theory) on context is ubiquitous. It's one of the known pathologies of Kolmogorovian probability theory and certainly comes into play when dealing with probabilities relating to incompatible observables. There is a whole area of research regarding this. To see a Nobel prize being awarded to a bunch of hype mongers promoting "quantum weirdness" that spits in the face of those working in the mathematical foundations of QM is very disturbing. The Nobel prize in physics has been dragged down to the same laughable level as the Nobel peace prize.
The fixed horse race analogy is deeply flawed. Much better is to realize that we'd know which horse would win *if we had sufficient information* on the state of every horse, the track, it's condition, how each horse interacts with that track condition, the rider, his state of mind, etc.
Of course... we don't -- and *can't* have sufficient information, since the systems are so complex.
This bothered me too!
Nah, all that information doesn't exist, which horse wins or loses is entirely probabilistic.
lol, Do they even listen to what they are saying? Has modern science become yet another echo-chamber?
Yep, I noticed that too. The analogy was all sorts of wrong.
As I understood it, kinda - except that the very reason we can't have sufficient information is that QM simply doesn't allow us, and this rules out any local hidden variables that would contain this information. Thereby making the system ultimately non-deterministic
@@erik-2820 too many classical physics laws absolutely function at (1) the macro level and (2) non-relativistic speeds for a horse race to be non-deterministic due to QM.
The weird thing being said by a few people here is the same physicists that came up with the universe being probabilistic are the same people who were saying "shut up an calculate". Bohr and whatnot were the ones that made Bell have to keep his work from his coworkers.
@OddPotato only when you do that last step of using the Born rule, but that can be derived in QM, it's not fundamental, as it's about trying to relate QM to our classical understanding of the world
I'm trying to figure out why they all, without exception, make sure to qualify their statements about the non-existence of hidden variables with 'at least locally'. At what non-local level could they still exist then?
There could be some hidden correlation between particles that is independent of distance. They could both, for instance, have instant access to some value anywhere in the universe. I.e. spooky action at a distance.
Bell in fact developed his inequalities to counter the then-prevailing attitude that "hidden variable theories" were impossible (based on arguments by von Neuman). He considered that they would prove that non-locality is fundamental to quantum mechanics, which was made explicit in David Bohm's "non-local hidden variable theory" now called Bohmian mechanics or pilot-wave theory, and which he thought was much more satisfactory than the dominant probabilistic interpretations as it dispensed with to him diffuse concepts such as "collapse" and "measurement". That Bell would have set out to disprove deterministic views of QM and preserve locality, as the video seems to suggest, is a complete inversion of the man's actual views.
Yes, Bell assumed that his idea of hidden variables was unassailble but that in addition QM was non-local and that non-locality explains QM violations of his inequality. Except he failed to realize that locality is a redundent assumption and that the inequality is derivable solely from his unthinkingly assuming that there is a such a thing as a single joint probability distribution that one can use to average over. Realism is also redundant, as Eberhard showed any theory whether with hidden variables or not that simply treats the observables as being defined on a such a common probability space produces BI and will be inconsistent with QM.
Several statements are made like "there are no hidden variables, at least locally." I'm curious about this clarification that keeps being added. What would a non-local hidden variable mean or look like and why is that not ruled out?
If the hidden variables are non-local, there’s no reason the two entangled systems can’t instantaneously make use of shared hidden information to recreate the predictions of QM.
My very basic understanding is that until the entanglement experiments are done at a huge distance, outside influences cannot be ruled out completely. But at the distances tested, it doesn't seem to be the case
@@barcodebarcodebarcode Bell’s theorem tells us that a _classical_ theory which recreates the result would have to be non-local, not that QM actually _is_ non-local.
@@barcodebarcodebarcode It's a fair point, but I think this is ultimately due to John Bell's wording. Since the context is that of hidden variable alternatives to QM, "local" implicitly means "classically local". If you look at what's happening from QM's point of view, there's nothing non-local going on.
My understanding is that a non-local variable would be a global variable. Perhaps a scalar field that determines the up and down nature of spin experiments.
I’m curious for a video about Global hidden variables, since even John Bell said it’s a valid explanation and compatible to the Bell’s inequality.
The thing is, how could the existence of global hidden variables ever be confirmed?
Also: Superdeterminism.
@@realdarthplagueis I think this video explicitly ruled out super determinism
@@billoddy5637 Wasn't superdeterminism created as a solution to Bell's inequality with hidden variables? Even with local hidden variables.
The thing is that people view things like that like crazy. But to me the idea that the universe is producing true randomness is more scary. That means the universe is capable of doing something that cannot be done on a Turing machine. Essentially meaning the universe can hypercompute, no? It might be one of the simplest hypercomputations on the face of it, but it's still beyond normal comutation. If hypercomputation can exist, then personally I think that just completely throws maths into disarray,
These experiments prove that QM is probabilistic, not deterministic-a hidden variable is an invalid description of the regimes QM describes.
I'm definitely someone who struggles to imagine that there isn't still some secret determinism in there somewhere. Like Tony's example with flipping the coin - a coin flip or a dice roll is the basis of how I think of 'probability,' but if could somehow control all the variables to flip the coin or roll the dice in exactly the same way each time, I would expect to get the same result each time.
So it's very hard to understand a truly probabilistic system where even when all the variables are identical you can get two different outcomes. I can accept that it's true but my simple mind has spent its entire existence understanding that every effect has a cause. Breaking that absolutely does make me feel uncomfortable.
i think the only way to not feel uncomfortable with it is to just stop thinking about it. it's a basic feature of the human mind to always look for cause and effect. quantum mechanics only follows that if you look at the wavefunction itself and not the probabilities it describes. maybe one day we'll have a more intuitive description of how it all works.
Yeah, most “probabalistic” things we usually think of could probably be modeled well enough to predict the outcome, except QM. Very interesting.
Why can't there just be sub states of these systems that we can't observe interacting to appear not deterministic?
What if a higher dimensional shape has an attribute that can only interact in a dimension we can't observe, but a physical shape we can see in 3d space?
That shape stays still to us, but collides at a higher dimension, changing the sub state at that level, and then propagating that back to the realm of observability.
Would that not just be determinism with more steps? I don't get why it must be non deterministic yet.
It's worth noting that Bell's Inequality only rules out LOCAL hidden variables. John Bell himself admitted that GLOBAL hidden variables are still possible and compatible with the theory. But afaik nothing has come of that so far.
@@ArawnOfAnnwn what would global hidden variables imply? some property present everywhere in space at once?
Honestly I thought that the bells inequality video was an emergency Nobel video. With wizardry to get the visuals in so fast.
That outlook meeting alert at 5:53 was a quantum notification because it made me check my work calendar 😂
8:57 - I'll tell you why. It's because it's incompatible with relativity. If influence can travel faster than light in some reference frame, then it can travel backward in time in another frame.
Sixty Symbols: "The universe is random and not deterministic."
Also Sixty Symbols: uploads video on entanglement an hour before the Prize is announced.
Yeah, you're really not helping your case here.
Please do a follow-up about global hidden variables and the EPR = ER theorem
My question is, why are we only limiting this experiment to "3 switches" ?? It seems that you could add more switched states and come up with totally different probabilities.
What I don't fully understand is why it is "there can't be more physics to it" and not "it can't be this specific kind of more physics". I'm pretty sure it's somewhere in between, but I've yet to see an explanation that I can fully understand. I also don't think that last guy at the end understands the parts of the issue that aren't philosophical, the issue I see with it is understanding how this can work: you see the result of one random event, and knowing it determines the result of another event that should have also been random but now isn't for you. Is there actually a problem with that? I don't know
Bell's Inequality doesn't categorically rule out state variables. What we can rule out is a constant state variable that has no time-varying perturbations around some ergodic mean. Bell allowed that the presumptive state variable could include a time-varying component. The most obvious one to consider would be something akin to Larmor Precession around some ergodic mean spatial direction of the magnetic moment vector. In order for the math to work, one then has to adopt a framework in which timekeeping is uniform everywhere and everywhen, so that the presumptive state variable can be treated as a odd function, so that λ(x,t) ≡ -λ(-x,t) for all x and t. But under GR, we know that timekeeping varies from one location to the next, due to the presence of any gravitational gradients along the path of an integration. That is, Bell would have needed to employ a gravitational path integral to account for differential phase shift in the time-varying terms in λ(x,t). Since we have no practical way to account for gravitational gradients, we are left to reckoning the effects of decoherence (loss of ideal phase-locked synchrony), and this explains why Bell's Inequality is inapplicable to our cosmos where time-keeping is local.
I'm at work and the outlook meeting notification at 5:52 gave me a mild heart attack 😂
same!
Yeah I was looking for it so hard like, what did I miss?!
Yeah I also FIRST looked into the outlook tab, THEN rewound the video to check :D
Probability is a mathematical construct we use to describe things when we don't have all the information, I have a hard time accepting or understanding it as ultimate reality. Can't it be the case that things seem to be probabilities because we can't possibly control our experiments or have all information when carrying them out?
I thought color was an intrinsic property of matter. Until I learned that at suficiently small scales, visible light can't interact with objects at that scale, so most stuff are "invisible". Using that analogy, maybe, things just become probabilistically fuzzy when we go to quantum scales. At least as long as we are talking physics. All of physics are just approximations anyway. That doesn't mean that the world really works that way. But until we develop a better tool, if probabilities explain that phenomenon better (and make our internet faster), that's the way to go. The irony is that many people that wanted to discredit QM, actually contributed to its foundation. Even if it conflicts with our existing beliefs and axioms, after a century of disdain and doubt, I think we can at the very least grudgingly start accepting the probabilities are here to stay (like Gödel's incompleteness theorems). Btw, I prefer determinism too. Anybody claiming that he likes the probabilities in QM is a flat out lier.
@@JamesSarantidis I have no problem accepting probabilities as the best way so far to describe what's going on, but that would be a quality or limitation of knowledge, not of ultimate reality (can we even truly know reality except what we assume about it?). So when the last professor says nature itself is probabilistic, not deterministic, I'm very curious as to how he or the Nobel prize winners reached that conclusion.
AFAIK determinism isn't a discovery or a statement about knowledge, it's an assumption about reality itself, required by modern science.
I'm sorry but I don't think it's the same as your color analogy, because color is just being used as a name for something we can't describe, except by comparison to something else with similar properties. Unless I missed your point.
There is much evidence that some quantum processes happen with undetermined outcomes. Assuming that all probability comes from a lack of information is a leap of faith that determinism must ultimately be true regardless of the current evidence.
@@Nighthawkinlight I'm very ignorant of quantum processes, but evidence can't prove or disprove determinism, it's an a priori assumption. That's like an experiment showing that evidence is meaningless or the scientific method is flawed, scientists can't shoot themselves in the foot.
Even if all evidence points to probability best describing reality, it can't prove they happen outside determinism (unless I'm missing something, which is very likely).
@@danfg7215 Bell's inequality assumes two things, locality and realism, one of those has to be wrong, but it doesnt have to be the realism. Nonlocal hidden variable interpretations are still viable, like De Broglie Bohm interpretation. Bell knew this, but not many in physics today seem to.
In 1952 I saw the impossible done. It was in papers by David Bohm. Bohm showed explicitly how parameters could indeed be introduced, into nonrelativistic wave mechanics, with the help of which the indeterministic description could be transformed into a deterministic one. More importantly, in my opinion, the subjectivity of the orthodox version, the necessary reference to the ``observer,'' could be eliminated. ... But why then had Born not told me of this ``pilot wave''? If only to point out what was wrong with it? ... Why is the pilot wave picture ignored in text books? Should it not be taught, not as the only way, but as an antidote to the prevailing complacency? To show us that vagueness, subjectivity, and indeterminism, are not forced on us by experimental facts, but by deliberate theoretical choice?
--John Bell
Experiments vindicating Bell’s Theorem don’t show that Nature is fundamentally indeterministic. Also, Bohm’s theory is *non-local* and is, therefore, compatible with Bell’s Theorem. It’s funny how little history of physics actual physicists know on this issue. Bohm’s theory exhibited non-locality before Bell wrote his theorem and was the inspiration for Bell to write it in the first place. Not only that, Bell was one of Bohm’s most vocal defenders until his untimely death.
It doesn't specifically say it's probabilistic. You do mention as an aside "at least locally". It may in fact be determined by something non-local, or more outlandishly (but not excluded) it could be that the underlying nature of space-time means these apparent particles are in fact still projections of a single particle into space-time, and by definition anything is local in their reference frame, by some other non-cartesian structure (a little bit like the concept of wormhole perhaps). Or potentially other mechanisms we haven't thought of. The mechanism isn't necessarily a probability, there could still be a specific mechanism that makes a deterministic choice based on something we don't know about, but it happens to both (or the combined one). Obviously I'm not saying it is, but I don't think the proof actually proves probability specifically, just delayed choice and simultaneity (whatever that means in relativistic space-time). Probability is just a convenient way to describe it without knowing more. Or it may really be probabilistic, but it doesn't prove it.
So I think it's basically overstating the proof.
It's still one of the most profound proofs ever, for sure. Stunning piece of thinking and of subsequent experiment.
Well, there is always the possibility, that QM just violates statistical independence, sort of the third pillar of bell's inequality (besides locality and realism). But this would imply superdeterminism.
as if there was anything wrong with superdeterminism...
The previous video about Bell's Inequality was fantastic. But I still don't really understand why there can't be a hidden variable or how it proves, as said in this video, "that there is no more physics to be discovered." I'm not arguing against that idea, I just don't feel that it's been explained. For example, why can't there be some other quality of particles that hasn't been discovered and that is responsible for the different statistical outcome revealed by Bell? And how does entanglement "prove" that reality/quantum is statistical? Doesn't it in many senses just the opposite? It says if the spin of one particle is down, the other will be up - not that the other "might" be up.
I feel like the “local” aspect is often glossed over, especially in this video. That seems like the final potential loophole. How serious are theories of non-local hidden variables?
Every since the dawn of humanity, everything we didn't understand was considered just random. The problem here is that you get random results when you do the testes. The problem is that it discourages investigation. That's the sad part.
so how exactly do you measure a single electron? or a single quant of light?
What bothers me in these videos is the single-minded focus on interpretations of quantum mechanics with wavefunction collapse, without so much as a nod to the possibility of a non-collapse interpretation. To my mind, non-collapse is not only the more elegant model, but more easily makes sense of the experiments in which we see weird wave-particle effects and the dreaded "spooky action at a distance". More importantly, it eliminates the gaping hole in the model which postulates wavefunction collapse but lacks a description of what a "measurement" even is and how it causes the wavefunction collapse in terms of the properties of a physical system. Perhaps I'm out of date on that, but without some physical mechanism for wavefunction collapse, I can't help but think non-collapse is the more natural interpretation, and the appearance of collapse is likely just an emergent phenomenon. Since in this video you all seem to strongly favor collapse, I would be interested in hearing why.
I can't speak for the video authors, but since there are multiple of them, it would not surprise me if they represent multiple opinions about what's the best QM interpretation. There are a dozen or more - I know, I took Philosophy of Quantum Mechanics class twice and each one is more confusing (and better in some sense but worse in some other sense) than the last. If they tend to focus on the Copenhagen Interpretation, it is probably since that is the most well-known interpretation among general physicists who do not specialize in entanglement or quantum information theory, and perhaps among amateurs as well. I agree with your critique of the Copenhagen Interpretation and its collapse of the wave function mysterious event. I don't like it either. Let me quote your key sentence: "I can't help but think non-collapse is the more natural interpretation, and the appearance of collapse is likely just an emergent phenomenon." I kind-of think that if we had enough really smart physicists/mathematicians/logicians we could sponsor a project that would eventually prove the functional equivalence of some subset of the dozen or so QM interpretations. The ones not in this subset would either be cast on the heap of discard interpretations, or perhaps on the list of "yet to be proven equivalent."
Yeah, non-collapse is the only way to preserve determinism and locality.
These scientists say things that can be questioned from the perspective of the philosophy of science. They should be able to explain the difference between a probabilistic universe and a random universe without casuality.
Bell's theorem notwithstanding, I don't think we can call Copenhagen a complete description of nature. The discontinuity in wave function collapse isn't just dissatisfying, it's a hole in our understanding.
That is why I accepted Our Lord von Neumann into my life, and why you should, too. ;-)
Noble prize winners are a joke nowadays.
I hope they'll be a Periodic Tables video on click chemistry.
I think your videos are great and look forward to them. Thankyou for your uploads, they are extremely interesting and can be fascinating.
couldnt have said it better! ^__^
TLDR: reality is random
CHAOS REIGNS
Chaos is deterministic.
This is the best explanation of the physics nobel prize I've yet found -- thank you for addressing what this prize was for & not just giving a background on quantum mechanics like all the popular press I read.
"Probabilistic" just means that there are still unknown factors that are having effects that we are not understanding and not predicting. It just means that we are still not seeing things with enough "resolution", meaning that these things that you believe are the fundamental building blocks are still not the base level of construction of reality and there is yet another layer of construction below sub atomic particles that are actually constructing the sub atomic particles themselves.
Its easier to think of it on a higher scale as an analogy: If you were to look at any one molecule of gas in the atmosphere and try to predict exactly what it is going to do next or even project it into the future, your answers would be very probabilistic; because there are local factors, there is the influence from all the other gas in the atmosphere, there is the gravitation of the Moon, there is even the heat from the sun while on the other side of the Earth, etc: that all have effects on what any one molecule in the atmosphere does, and that's why predicting the weather is so difficult past a given stretch of time. There is "probability stacking" (aka tolerance stacking in the machining world), where there are too many possibilities happening, one after the other, for the 'reaction chain" to every be predictable. But at the same time, we still understand that what is happening in the atmosphere at the molecular level is very deterministic. Everything has a cause and effect and it is all interacting in a very predictable way, but with unpredictable outcomes due to the probability stacking. I believe it's possible that this same sort of thing is happening in these experiments; that there are far more complex things happening below the surface, and all that we are even able to see are the effects, but not the actual causes.
Just imagine I'm standing in a dark room with a ball on a string and I'm swinging it over my head, and maybe if you add heat I'll spin it faster, or cool the room and I'll spin it a little slower at times, maybe I swing that ball left and right or towards the floor, anywhere I want to. If you were to snap a photo in the dark -- you would see me swinging this ball around, but you could never know where that ball was going to be until you look. This is the "probability" that you speak of -- it's simply us being in the dark about certain parts of reality. You could continue to snap pictures in that dark room, some times the ball would be to my left and sometimes to my right, etc.. so you could say that it's actually everywhere in that room at once, until you snap that picture and know for sure. But to us it's a very simple situation, because we know that I'm just a person standing in the dark swinging the ball around -- so we can make sense of the pictures. When you're looking at photons or even sub atomic particles, you have no idea what is really going on in that dark room--- all you can see are the snapshots and their probabilities; but this says nothing to what is actually going on in that dark room of reality.
Maybe it was that "spooky action at a distance" was why you guys uploaded a video on Bell's inequality on the same day as the Nobel prize!
Definitely: Quantum Entanglement of Thoughts
Bells theorem has nothing to do with proving the world is probabilistic. And it has nothing to do with proving quantum mechanics correct. All these guys do not understand Bell and should view the talk by Tim Maudlin: “What Bell Did”
Ok, next year, Pr. Merrifield has to upload a video about Cosmic Strings, just before the Nobel prize announcement.
Quantum physics is like dating, clear rules and boundaries but everything in between is just probabilistic. You can never know until you ask
That "Spooky Action at a Distance" video is the most intuitive explanation of Bells inequalities that I've seen so far.
I think what people object to in the probabilistic model needs a bit of an adjustment to the metaphor:
It seems less like not knowing which horse is going to win and more like not knowing if it's a horse or dog race until you look and people making weird statements like "it IS a horse AND a dog race until you look!"
What's spooky about finding a left handed glove and then knowing its right handed pair is the other particle? Is spin not also a conserved property? You split a photon, send opposite polarized light off in two directions and then are shocked to find out they have corresponding states when measured. What am I missing here?
Determinism is not exactly falsifiable from an epistemological perspective. What we fail to do here is distinguish determinism and decidability. Whereas the latter is a function of a system's inability to converge upon computations within its own domain, the former is an essentially philosophical stance that lies outside of empirical testability.
8:45 you not only don't know until you perform the measurement, your measurement is also a significant part in constitutionalizing the result, i.e. observing something actually changes it 🔍👀
"end of the story" is a little overstated.
Lots of folks here mentioning global variables being glossed-over.
But what about the question: "why gravity?"
"At least locally"... is there anything to say about hidden variables in a global way?
Many people have believed they have reached the end of physics, but every time they have been wrong. I am sceptical to saying that this IS the end.
When Einstein went to see the movie Ghostbusters why did he sit all the way in the back row? Because he wanted to see spooky action at a distance.
The horse racing analogy really brought clarity to the explanation for me
So great to see sir Phil Moriarty back again . Please upload his full conversation & thoughts on 2022's Nobel prize on the channel.
Fly By Night sighting! Rock on, brothers, and thank you for the video!
I study physics at the University of Vienna, and our dekan opened his congratulation speech with the word 'Finally'
Very fitting comment. U Vienna figures prominently in past and ongoing Bell experiments on photons.
Einstein is looking down from heaven with an annoyed grimace and Neils Bohr is looking up from hell laughing his ass off.
Terry Prattchet had it when he says Million to 1 chances come up 6x out of 7. lol
Did you know most of his audiobooks can be found on youtube? Had great fun during my convalescence.
9 times out of 10, but yeah.
I feel like some people are jumping to conclusions and just want this to be the end of the story. This isn't proof that the universe is probabilistic, it could be deterministic in ways that are simply "unreachable" for humans, as there is a limit on how much of the universe we can measure.
I don't understand why talking about the foudations and interpretations of quantum mechanics is such a taboo. Last year I took two courses on QM and not even once did our professors mention that what we're doing is the copenhagen interpretation. We talked about the double slit experiment at the very start as a motivator for why we interpret the wave function as we do but never talked about actual realizations of this experiment or about what the heck a "measurement" is. Physics is supposed to be all about understanding so that really put me off.
Moreover it seems that there's barely any research on the topic with theoretical physics focusing more on high energies, cosmology and quantum gravity.
It's such a shame too cause the foundations of QM were a really big motivator for me
In regards to the horse race analogy, I don't think that people believe there is a conspiracy or a matter of refusing to believe. Its more that we only apply probabilities to each horse based on the information we have _because_ we don't have _all_ the information. If we did have all the information there would only be one winner before the race with 100% probability that would have always won. The same rationality applies to flipping a coin, it's not in reality 50/50 if we knew the exact forces involved. If you flipped a coin under the exact same conditions a million times it would land on the same side every time. This is an entirely reasonable assumption at the macroscopic level, its just hard to lose that rationality when dealing with quantum mechanics.
I still can't bring myself to believe it entirely and subscribe to a more deterministic Global hidden variables model of the universe with the full knowledge I'm probably wrong. I also think the very notion of "probability" is an invention by the human mind and doesn't exist outside of our reality.
In the wise words of Ronald Macdonald: I won't change my mind, 'cause I don't have to. I won't change my mind on anything, regardless of the facts that are set out before me. I'm dug in, and I'll never change.
All of these guys are going to look silly in the future when Copenhagen is finally dumped for a deterministic interpretation like De Broglie Bohm. Bells inequality assumes two things, realism and locality. One of those has to be wrong, but it doesn't have to be the realism that is. A nonlocal hidden variable interpretation is still viable, as Bell knew, but modern physicists don't seem to understand that fact at all.
Not deterministic, but is mechanistic. Rolling a dice doesn't prevent it being a mechanical mechanism, that's certainly aloud.
And it's extremely reassuring, all and parts of disorganised and lightly attached system of information transfer can quantum tunnel to more organised places arbitrarily far, including between universes, in finite timescales.
The arrow of time points forward in time because of the wave function collapse. Because causality has a speed limit every point in space sees itself as the closest to the present moment. When we look out into the universe, we see the past which is made of particles. When we try to look at smaller and smaller sizes and distances, we are actually looking closer and closer to the present moment. The wave property of particles appears when we start looking into the future of that particle. It is a probability wave because the future is probabilistic. Wave function collapse happens when we bring a particle into the present/past.
Ok local hidden variables are ruled out. But I'd like to know more about the non-local hidden variables interpretations. How that spooky action at a distance is explained. I guess there's a way to rethink what space-time really is, there. No? How does QFT explain entanglement?
Happy to see them all. Thank you!
These guys are like the Wu-Tang Clan of physics
@@Olhado256 They should put that on their business cards.
My problem isn't in accepting a probabilistic universe, my issue is I don't understand how adding indeterminism lets you violate bells inequality. How does indeterminism allow for higher than expected correlations?
I LOVE that the video "Spooky Action at a Distance" was a spooky upload at a distance.
The fundamental difference between a horse race and particle spin is, the horse race hasn't happened yet. Quantum physics tells us that something that already exists isn't one thing or another till it's measured. It's like saying that the horse race is run with no spectators, only cameras, and after the race is OVER, but before we look at the video, neither horse has WON YET. The thing that has ALREADY HAPPENED could come out either way when we observe it. It's not that we don't KNOW yet, it's that it isn't ONE WAY OR THE OTHER yet, even though it's already happened. THAT'S why people have (or, at least, this person has) a problem with it.
would love to see numberphile like videos on the physic and chemistry channel
i demand more brown paper sheets now!
Super pleased for Aspect in particular. Dude's an experimental legend.
one thing that isn't probabilistic is that it's 100% true that any video chat or interview will have a notification chime go off at some point during.
I was waiting for this to drop, thanks guys!
10:12 That still feels really presumptuous. I feel like physicists need more philosophy if they're gonna jump to that conclusion.
How do we tell if it’s really random or based on some chaotic interaction. If it was chaotic it would look more like a classical kind of probability. If it was random you could expect like 5000 head in a row
The Irony was that at School A-Level physics quantum mechanics was avoided..it was circumnavigated...everything was Newtonian. In A-Level Chemistry quantum physics was an essential but we were never to question it or pry into it. That was sacrilege.
Great video. Still my favourite channel on CZcams!
A few things on this subject:
a) How does the pilot wave theory come into this? Is it a hidden variable theory that can be ruled out?
b) I think it's dangerous to say "quantum mechanics was right" since we know there's an awful lot of pseudoscience out there that uses quantum mechanical terminology and hyperbole to its advantage. This news will only strengthen their arguments.
c) I like listening to Tim Maudlin's views on QM. He agrees with Bell's Inequality, but he also rules out as much quantum woo as he can - he hates the idea of the "observer affecting reality" for example.
d) If we could do an up to date video on the double slit experiment, Schrodinger's Cat, and psuedoscience / woo in general that would be great.
"Probabilistic" just means that there are still unknown factors that are having effects that we are not understanding and not predicting. It just means that we are still not seeing things with enough "resolution", meaning that these things that you believe are the fundamental building blocks are still not the base level of construction of reality and there is yet another layer of construction below sub atomic particles that are actually constructing the sub atomic particles themselves.
Its easier to think of it on a higher scale as an analogy: If you were to look at any one molecule of gas in the atmosphere and try to predict exactly what it is going to do next or even project it into the future, your answers would be very probabilistic; because there are local factors, there is the influence from all the other gas in the atmosphere, there is the gravitation of the Moon, there is even the heat from the sun while on the other side of the Earth, etc: that all have effects on what any one molecule in the atmosphere does, and that's why predicting the weather is so difficult past a given stretch of time. There is "probability stacking" (aka tolerance stacking in the machining world), where there are too many possibilities happening, one after the other, for the 'reaction chain" to every be predictable. But at the same time, we still understand that what is happening in the atmosphere at the molecular level is very deterministic. Everything has a cause and effect and it is all interacting in a very predictable way, but with unpredictable outcomes due to the probability stacking. I believe it's possible that this same sort of thing is happening in these experiments; that there are far more complex things happening below the surface, and all that we are even able to see are the effects, but not the actual causes.
Just imagine I'm standing in a dark room with a ball on a string and I'm swinging it over my head, and maybe if you add heat I'll spin it faster, or cool the room and I'll spin it a little slower at times, maybe I swing that ball left and right or towards the floor, anywhere I want to. If you were to snap a photo in the dark -- you would see me swinging this ball around, but you could never know where that ball was going to be until you look. This is the "probability" that you speak of -- it's simply us being in the dark about certain parts of reality. You could continue to snap pictures in that dark room, some times the ball would be to my left and sometimes to my right, etc.. so you could say that it's actually everywhere in that room at once, until you snap that picture and know for sure. But to us it's a very simple situation, because we know that I'm just a person standing in the dark swinging the ball around -- so we can make sense of the pictures. When you're looking at photons or even sub atomic particles, you have no idea what is really going on in that dark room--- all you can see are the snapshots and their probabilities; but this says nothing to what is actually going on in that dark room of reality. ;;//
I just realised I've cited some of Ed Copelands papers. Oh my god. Two in particular are "Exponential potentials and cosmological scaling solutions" and "Dynamics of Dark Energy". Hi Ed if you see this! Thanks for helping me write my Literature Review on dark energy!
timestamp: 1:01-1:33 & 7:58
Fascinating. It’s satisfying to get confirmation of a very unscientific, over simplistic notion I have about the fundamental nature of the universe.
It must be random, at a deep, original level. A deterministic universe would be like a pencil that is finely balanced on its tip forever. Nothing can happen essentially. The fact that there is a fundamental randomness rooted in the universe is what allows change and evolution (of elements as well as complex systems) in the first place. If the universe were not random, it would probably not even come into being (probability pun not intended).
My naive understanding of entanglement is that events happen in parallel somehow, without any causal connection or interaction. (Kind of like the video being released on the same day as the Nobel prize was announced!)
There may be a prior starting point that gave rise to the more than one parallel events appearing to be related in some way (like rainfall giving rise to my putting on my raincoat and the dog lapping up water from a puddle: putting on a raincoat did not somehow cause the dog to drink from the puddle, or vice versa). The same actions don’t always happen together, but perhaps they are very likely to occur in a seemingly related way, but it’s random cause the dog might not be thirsty on one occasion and I might not wish to go out on another occasion. Yet they seem to happen simultaneously at a distance without any means of communicating between myself and my dog.
Two principles that seem baffling at a quantum level, but could actually be the nature of randomness (if there were no randomness, the universe wouldn’t spark into existence in the first place) and parallel but unrelated phenomena.
(I think)
It seems like Bell's inequality is to physics what Gödel's theorem is to mathematics
Horse races are probably basically deterministic on the timescale of a few minutes. Their results are the outcome of many hidden variables such as the state of the horses, riders, track, air... large classical systems.
Have you failed to grasp any other concepts?
The professors seems to keep saying there are'nt hidden variables locally. What does that mean?, is it saying that hidden variables are impossible or there are global hidden variables instead?
It's how they avoided acknowledging that the Nobel Prize-winning results vindicated NON-LOCAL interpreations of quantum mechanics.
sorry, but isn't DeBroglie-Bohm a nonlocal hidden variable theory? afaik Bell's theorem doesn't touch the Bohm interpretation as it only speaks to local hidden variables.
I love that Clauser was recognized, just because he seem like such a nice bloke from the youtube videos I've seen of him.
at least locally..... at least locally. ...at least locally.
I'm really disappointed that the consequences of the "at least not locally" caveat weren't discussed
Im just humming fly by night over and over again now.
I have few questions..what is quantum mechanical description of current electricity/ magnetism? What is description of gravity..?Why macroscopic and quantum mechanical things appears to behave differently??? Can we derive Newton's laws of motion using quantum mechanics?
More videos need to be on the channel please
I don't think it's a validation that the universe is probabilistic at all. There are other interpretations- many worlds, collapse theories, and the most controversial of them all, Superdeterminism. To me Superdeterminism is the most likely candidate, as it requires the less amount of work, and doesn't have the kind of jumping through hoops neccessities as the other interpretations.
I'm looking forward to your video that will explain the "reality" behind entanglement. Quantum wormholes? Does wave function collapse at the speed of light?
It's clear that John Stewart Bell did get the 1990 Nobel Prize for Physics in worlds in which he did not die prematurely.
Gotta say. That was a bit of a head scratcher when the video came out, and then the Nobel Prize discussed it…I thought for a few min that your video knew ahead of time! Well done 👍 😄
0:07 Prof. Copeland's expression of fear and intimidation is Oscar worthy 😂
about 5:40 they talk about the injustice to J.S. Bell. This was the perfect time for the Nobel Committee to scrap it's posthumous restriction once and for all. Bell is the man responsible. A silly rule that only cheapens the prize.
I am pained by the omission of Everettians from this video. There's an obvious assumption here that the universe is necessarily probabilistic simply because our experiments say it is probabilistic - which is true only if we are *not quantum observers*, an idea that seems patently absurd to me as a Materialist.
I'm not sure why everyone now claims that this disproves any determinism. Maybe it is the case, but as far as I understand it this still does not disprove non-local deterministic theories. I'm not saying thare has to be some underlying theory, but claiming that this proves Randomness is not correct. Or am I totally missing something?
Isn't the many worlds interpretation of quantum mechanics another way of interpreting this? So, instead of saying that the world does not obey local realism you instead say that all possible outcomes of an experiment represents valid representations of the (many) worlds that actually exist?