Eise

2 hours ago, joigus said:

You could at least listen to the videos you post, @bangstrom

It is even worse. @joigus, Sabine H has a blog, in which she spells out her videos, so you can read them in your own tempo. Here is the one of that video. And this is even 'worse' than what you quoted:

Quote

So, oddly enough, quantum mechanics is entirely local in the common meaning of the word. When physicists say that it is non-local, they mean that particles which have a common origin but then were separated can be stronger correlated than particles without quantum properties could ever be. I know this sounds somewhat lame, but that’s what quantum non-locality really means.

And in the comments. A commenter:

Quote

If the observed correlations are greater than those allowed by the theory of quantum mechanics, then it is a misnomer to say that (the theory of) quantum mechanics is nonlocal.

Sabine Hossenfelder:

Quote

Wot? The correlations are greater than those allowed by a deterministic, local theory, not by quantum mechanics.

Next try!

6 hours ago, bangstrom said:

The mainstream view among physicists is that non-locality has been demonstrated as ‘real’ with few contrary opinions such as those of Gell-Mann or Kracklauer. With the exception of those two, the vast majority remaining are the ones that do think non-locality is real.

You keep repeating this. But my list becomes longer...

• Susskind
• Gell-Man
• Kracklauer
• Sidney Coleman (thanks, Joigus)
• Sabine Hossenfelder

2 Names added on the list thanks to your references...

For clarity, let's take the following 3 propositions

1. QM does not allow for FTL causation. Watch my wording: causation. So no signal, (inter)action, affect, or whatever.
2. The conclusion of Bell's theorem is: no local hidden classical system can reproduce the correlations predicted by QM.
3. These correlations were experimentally confirmed, so QM is right.

Conclusion: the experiments can be explained by QM, without needing non-locality. Classically, we would need non-locality.

So find an acknowledged author that rejects one of the 3 presumptions that together support that QM is local.

If you keep repeating that the mainstream think QM is non-local, then it should be easy. But be careful not to shoot yourself in the foot again.

1 hour ago, joigus said:

Not surprised. I agreed to that one. Here's what I said:

15 hours ago, joigus said:

Now for buckyballs --I guess that's what you mean-- those are fullerene particles very common in interstellar soot, so I'm guessing it's possible in principle, like in the case of silicon atoms, although extremely difficult. I already gave you a reference to macroscopic superpositions of bunches of silicon atoms, but again you missed it.

Give us the reference to your Schrödinger water bears, please. I wanna have a good laugh.

Water bear = tardigrade

Essentially no different from experiment with a number of silicon atoms (the fullerene experiment.)

I know what you said. My point was against how you argued for your position. Counting particles is not of importance, mass, or better momentum, of the bound system is of importance here.

1 hour ago, joigus said:

In fact, it doesn't even make sense: What does it even mean to entangle non-identical things?

Good point. It were interference experiments, not entanglement experiments. But if bangstrom cannot just deliver tardigrades, but also a source of identical, entangled tardigrades, we could do the experiment. However, I am not sure to look for correlation or anti-correlation. Before I prepare the experiment, I have e.g. to know if tardigrades are bosons or fermions...

5 hours ago, bangstrom said:

I can name one more who might agree with Gell-Mann and Susskind and that is A.F. Kracklaurer.

No, you turn it around: instead of providing references of QM specialists who see 'real superluminal connections', you provide a link to a physicist who denies none-locality, strengthening my position. Try again.

5 hours ago, bangstrom said:

If you pass a single particle through a single slit, it produces an interference pattern due to diffraction.If you pass a single particle through a double slit it produces a double slit interference. If you try again with 3,4 or 5 slits, you get increasingly complex interference patterns.

Yes, you are completely right. I would suggest that you read Feynman's QED: The Strange Theory of Light and Matter. Then you can wonder why the principle of least action seems to work in classical physics (Lagrange formulation of classical physics, Fermat's theorem etc), in relativity, and in QM (QED). E.g. taking Fermat's theorem, how does the light in advance know what is the fastest way between two points? Must be non-locality... .

16 hours ago, Eise said:

Not with tardigrades. But if you have a source, let us know.

 OK, this was already reacted on by Joigus.

However, @joigus, I think you make an error in your argumentation. Interference experiments with buckyballs have succeeded.

Quote

Quantum superposition lies at the heart of quantum mechanics and gives rise to many of its paradoxes. Superposition of de Broglie matter waves has been observed for massive particles such as electrons, atoms and dimers, small van der Waals clusters, and neutrons. But matter wave interferometry with larger objects has remained experimentally challenging, despite the development of powerful atom interferometric techniques for experiments in fundamental quantum mechanics, metrology and lithography. Here we report the observation of de Broglie wave interference of C60 molecules by diffraction at a material absorption grating. This molecule is the most massive and complex object in which wave behaviour has been observed. Of particular interest is the fact that C60 is almost a classical body, because of its many excited internal degrees of freedom and their possible couplings to the environment. Such couplings are essential for the appearance of decoherence, suggesting that interference experiments with large molecules should facilitate detailed studies of this process.

But if I follow your argumentation regarding the tardigrades, and apply this to buckyballs, that would have been:

• 60 x 6 = 360 electrons
• 60 x 1 = 60 nuclei
• makes 420 particles

Or should I go further, and count the nucleons? 

• 60 x 6 = 360 electrons
• 60 x 12 = 720 nucleons
• makes a total of 1080 particles.

I simply think, that because the nucleus is a bound state, it counts as one. The same for carbon atoms, the same for buckyballs. And I would then assume the same for basket balls, tardigrades in between, both being also huge bound states of matter. So I even think bangstrom's idea is correct, but the experimental confirmation may lie in a very far future.

So I think you should just take the Broglie wavelength of the bound state as a whole. Sadly enough, Wikipedia does not mention the mass of tardigrades...

Maybe in the far future we will have amusement parks, where they send you through two doors, so you can experience yourself what it is to go to through 2 doors at the same time. 😉. Why not, you can already experience free fall...

19 hours ago, NTuft said:

In keeping with your philosophical approach, I think we must establish first principles, and I for one do not have a handle on the basic math assumptions that underpin QM, so I strongly recommend you do not completely accept what rolls out, if you don't either.

I am not aware of any QM physicist who would not agree with Susskind's position:

• Nothing that Bob does has any FTL influence on Alice's side. QM does not allow for such interactions. 
  If you know of FTL interactions (i.e. FTL causal relationships allowed by QM), let me know. This would mean that the direction of cause to effect is agreed upon by all observers.
• Bell's theorem says that no classical theory can replicate all predictions of QM

If you have any serious references, please post them.

You're right of course that I cannot evaluate the correctness of Susskind's calculations. But for this kind of situation, there is only one option for me: wait, and see if this is (will be) a well established viewpoint of the physics community at the long term.

As you call my approach 'philosophical', I would like to tell what my position is: in QM we have come at the limit of our, human, epistemological possibilities. We can measure particles arriving at a detector, measure some of their properties (but not all of them at the same time), or we can measure wave properties in the collective behaviour of many particles. These are physical, measurable results. But the wave function is not physical: we cannot measure it in itself. We cannot measure it (any experiment measuring the phase of the wave function? Or when it flips due to entanglement with a remote measurement?). It is part of a recipe to predict quantum events, but only in terms of probabilities. The wave function itself is not a physical object.

Earlier I compared it with the use of the imaginary i. AFAIK QM cannot be done without it. It is not just shorthand to make some calculations easier, as it is in the description of classical wave mechanics. And this imaginary i stares you in the face in the Schrödinger equation! (Just to be honest, I read somewhere (I think it was in the blogs of Sabine Hossenfelder) that much of QM can be done without imaginary numbers, but not everything).

At least I find it funny that a function is taken as a physical object. That its name is still a 'function' is at least suspicious. That is also the reason I cannot take MWI seriously. It heaves the existence of the wave function from a mathematical tool to physical reality. That is metaphysics.

13 hours ago, bangstrom said:

If you are looking for an argument form authority, I suggest you broaden sources. From my reading of the literature, non-locality is largely settled science and contrary views are far from the mainstream.

OK, give some of the same caliber as Gell-Mann and Susskind, that base their position on established mathematics of QM. Not of some metaphysical interpretation of it. (I found nothing of the kind in Susskind's book, just descriptions of experiments and mathematical derivations).

1 hour ago, bangstrom said:

In the past I considered entanglement at the macro level to be impossible but some experimenters have claimed to have achieved entanglement at the level of Buckey balls and even tardigraves.

I think you are confusing entanglement with plain superposition. I also know of experiments where they succeeded in doing double-split experiments with buckey-balls, and producing interference. Not with tardigrades. But if you have a source, let us know.

2 hours ago, bangstrom said:

This is a highly irregular statement. QM permits superluminal signaling, and ‘signaling’ is a word frequently used. The classical view does not permit superluminal signaling.

OK, I will cite a few lines from Leonard Susskind's Theoretical Minimum: Quantum mechanics. First he makes a mathematical derivation, that is of course is over my head, but the end conclusion is clear:

Quote

Nothing that happens at Bob's end has any immediate effect on Alice's density matrix, even if Bob and Alice are maximally entangled. This means that Alice's view of her subsystem (her statistical model) remains exactly as it was. This remarkable result may seem surprising for a maximally entangled system, but it also guarantees that no faster-than-light signal has been sent.

With other words, QM does not need faster than light signals to explain entanglement, and QM obeys this speed limit. Recognise what Gell-Mann said in the video that Joigus linked.

Then Susskind presents a setup with two computers, that each for themselves simulate quantum spin measurements, which is not impossible, if the random generator is good enough. However, he shows that in order to simulate entanglement, a faster then light connection is needed.
 

Quote

But doesn't this mean that locality-violating information can be sent through the cable? It would, if Alice, Bob and Charly were allowed to do anything that non-relativistic classical systems can do, in other words, systems that permit signals to be instantly. But if the only operations that are allowed are those that simulate quantum operations, then the answer is no. As we've seen, quantum mechanics does not allow Alice's density matrix to be affected by Bob's actions.

   This is not a problem for quantum mechanics. It is a problem for simulating quantum mechanics with a classical boolean computer. That is the content of Bell's theorem: The classical computers have to be connected with an instantaneous cable to simulate entanglement.

(Italics in the original).

So now you can do three things:

• show that Susskind made an error in his math
• stick your head in the sand
• or accept what one of great QM specialists is saying here.

For me, I accept Susskind's, Gell-Manns (and Swansont's, and Joigus', and MigL's) position, even if I cannot follow the math. So I take the argument of authority. Such arguments are valid, when it is clear that Susskind and Gell-Mann are absolute 'quantum experts'. Just to give an idea of Gell-Mann: he predicted the existence of the Omega-minus particle, and is one of the fathers of the quark model of hadrons. I think for him this topic would be basic QM...

2 hours ago, bangstrom said:

The timing of the ‘whatever’ has been frequently measured in experiments to be superluminal so how can you claim superluminal is an illusion?

Because QM is right: the 'superluminal correlation' is only needed when you want to understand entanglement classically.

Hi Joigus,

No, I do not want to take the deep dive into the principles of the so-called 'quantum teleportation'. AFAIK, Zeilinger was the first experimentally proving that it is possible. I do not quite understand it, and I will not spend my mind energy on that now. I mentioned it, because I suppose that Bangstrom's idea of 'identity swapping' comes from these experiments, and not from entanglement experiments 'an sich'. It is an application of entanglement.

1 hour ago, bangstrom said:

Yes, but that is from the human perspective.

Yes, and you are human. And humans do not have the ability to visualise what is 'really going on'. That is why you have a problem here. As any other human. But QM is unambiguous: the measurements are local, but correlated. 

1 hour ago, bangstrom said:

A superluminal signal is not possible by classical means. I don't know if you could even call it a 'signal' because it is instant at all points and has no direction.

I think your postings are scattered with 'signal', 'cause', 'affect', 'action' etc. In QM superluminal signals are also impossible. The illusion of a superluminal signal only appears because one wants to understand what is happening from a classical viewpoint.

1 hour ago, bangstrom said:

A superluminal signal is not possible by classical means. I don't know if you could even call it a 'signal' because it is instant at all points and has no direction.

Correct. So there is no signal, and it is superluminal? 

Reminds me of a bonmot of Pauli about Dirac's atheism: there is no God, and Dirac is his prophet.

1 hour ago, bangstrom said:

I agree ‘properties’ is a better term but ‘identities’ is the term I first encountered in my readings on the topic and I think even Zeilinger now speaks of ‘identity swapping’.

I assume this is in the context of 'quantum teleportation'. Quantum teleportation is based on entanglement, but it is a good trick, made possible on the basis of entanglement.

1 hour ago, bangstrom said:

Good point but what word would you suggest?

Correlation. That is what we (if I may speak for Joigus, Swanson and MigL...) are calling it all the time.

1 hour ago, bangstrom said:

Why do you say the experiment near Geneva rules out the superluminal nature of entanglement?

Because in this experiment, there is no direction all observers can agree upon. Detection1 can be the first for one observer, while for another observer Detection2 is the first. So there is no superluminal signal from one detection to the other, because a signal always has a direction. Hiding behind the vague word 'nature' does not help you.

1 hour ago, bangstrom said:

This defies our classical visualization

Yep. Nature is not obliged to follow our capabilities to visualise how this happens; our visualisations are classical, per definition. The superluminal signal is only necessary if you want to reproduce entanglement with classical means.

I scanned through Susskind's Theoretical Minimum about QM: he is making this argument very precise. Classically you would need direct action at a distance; QM does not. I would suggest to read this book.

1 hour ago, bangstrom said:

The correlated identities are not fixed from the start as...

Stop using the word 'identities', this is very imprecise. I assume you mean properties. If not explain what you mean with 'identity' in this context.

2 hours ago, bangstrom said:

Zeilinger's work with quantum teleportation demonstrates a superluminal transaction where an action at the source of an entanglement instantly- that is much too fast to measure- affects the observation at the other end.

Zeilinger would not agree with you, because your use of the word 'affects', which is just another way of saying 'one measurement causes a change at the remote side'. 

1 hour ago, joigus said:

What I've said is that no classical analogue can reproduce quantum mechanical correlations. So no coin, dice, gloves, cats, or whatever other classical mechanism can reproduce quantum correlations to their full extent.

I was breeding on a similar, precise way to formulate what we really learn from Bell-like experiments.

• In the first place, we learn that the predictions of QM are correct. (I suppose that is the reason that Feynman threw Clauser out of his office.)

Secondly, nearly the same formulation you used:

• No system, based on classical physics, can reproduce all predictions of QM.

Only if you would introduce 'action at a distance', one could. But we know this is classically impossible, because of SR.

@bangstrom: I think there is a rather clear experiment that shows that the correlation between the 2 distant measurements cannot be causal. And 'not being causal' implies:

• no communication is taking place between the two measurements, no superluminal signals
• none of the more or less equivalents of causality: effect, action, interaction, etc. applies.

Now this is the experiment: in a Bell like experiment the distances of the detectors are exactly equal. So, assuming we use a photon/polarisation experiment, int the rest frame of the source of entangled photons, the photons will arrive at exactly the same time. Further, the detections are spacelike separated, so even light is not fast enough to reach the other detector (maybe superfluous, because using photons in the experiment it would be impossible anyway. We measure the correlations, which of course are exactly as QM says they will be.

Now imagine 2 other observers: one is travelling in the direction of the first detector to the second, the other observer in exactly the opposite direction. For both observers, the detections do not occur at the same time. For Observer 1 Detection 1 will be the first, for Observer 2 Detection 2 will be first. However, SR demands 'conservation of direction of causality'. It cannot be that for Observer 1 Detection 1 causes Detection 2, and for Observer 2 Detection 2 causes Detection 1. Same holds of course for all other 'disguises of causality': communication, effect, interaction etc. This leaves us with the only other option, correlation. And as Detection 1 and 2 are outside their respective light cones, this correlation must have its origin somewhere else: the source of the entangled photons. 2 photons just leaving the entanglement source are of course in the light cones of Detection 1 and 2.*

And this is what Swansont has already repeated a few times: the photons are correlated direct at the beginning.

It is only when we look at it with a classical view, it seems we need 'action at a distance'. (That sounds like Joigus)

A bit against Joigus and Swansont, I would 'cry out': "yes, but we, as macroscopic human beings, live in a classical world!"

And therefore we are astonished about these results. But this is nothing new: QM is astonishing. But that is nothing new. Citations, just from my head:

Bohr: Who is not astonished about QM, has not understood QM.

Feynman: I do not understand QM.

* An actual experiment, not exactly like the one I described, but I assume equivalent, was indeed done:

Quote

We report on a new kind of experimental investigations of the tension between quantum nonlocally and relativity. Entangled photons are sent via an optical fiber network to two villages near Geneva, separated by more than 10 km where they are analyzed by interferometers. The photon pair source is set as precisely as possible in the center so that the two photons arrive at the detectors within a time interval of less than 5 ps (corresponding to a path length difference of less than 1 mm). One detector is set in motion so that both detectors, each in its own inertial reference frame, are first to do the measurement! The data always reproduces the quantum correlations, making it thus more difficult to consider the projection postulate as a compact description of real collapses of the wave-function

From: Experimental test of nonlocal quantum correlation in relativistic configurations

Bold by me, of course. Joigus, do you still not want to earn a beer?

11 hours ago, Eise said:

So a single measurement would do the job (except no scientist would do it once, it could be accidental).

A small correction to this: correlation always only shows up statistically.

10 hours ago, joigus said:

If you wanted to rule out something like that happening, you would have to go to non-parallel polarisers, and check whether they're giving correlated answers to uncorrelated questions, so to speak. I'm not sure that Alain Aspect did rule out that possibility, but I would be very surprised if he didn't.

It is my understanding that this is already accounted for in Bell's unequality: QM measurements cannot be reproduced by introducing any local hidden variables. I think 'hidden' is the keyword here. 

Compared to the Clauser et al experiment, Aspect changed the polarisers after the photons left the source, and also did this so fast that it was impossible for the measurement devices to communicate, i.e. they were spacelike separated.

BTW, I am still sitting on my problem...:

16 hours ago, Eise said:

The one with the clearest explanation where my error lies, gets a free beer (entangled with the one I will drink then, so take care it does not spill over...).

1 hour ago, bangstrom said:

A polarizer at the source is that first measurement.

Then you have not understood my example. The source of the entangled photons lies in the middle between Geneva and Andromeda. No measurement is made there. The measurements are done in Geneva and Andromeda. No beer, sorry.

34 minutes ago, geordief said:

Or has this measurement been made with just 2 entangled particles and the outcome is predictable on each occasion?

To add to Joigus' reaction: the correlation is 100% if the polarisers are oriented in the same direction. So a single measurement would do the job (except no scientist would do it once, it could be accidental). However, the 100% correlation is not interesting, because it could just as well be explained by supposing the photons had their polarisation from the beginning. To show the stronger correlation, you must vary the orientation of the polarisers independently from each other. And that you can only do by doing many measurements, according Joigus' example. Only then the correlation turns out to be stronger than a classical theory, where the photons have a polarisation from the beginning.

12 hours ago, MigL said:

IIRC, W Heisenberg developed Matrix Mechanics based on spectral line emission experiments; then again, he was supposedly high on cocaine on Helgoland Island, in the North Sea.

11 hours ago, joigus said:

Interesting. I thought he was just suffering from hay fever and went to Helgoland, where he went through an epiphany...

Yes, what Joigus says here is also what I read everywhere. The landlady of the apartment on Helgoland thought Heisenberg had been in a fight or something, so bad he looked in his face. I've been on Helgoland: it is a small rocky island, very different from the main land around it, and I can't even remember that I saw one single tree. Pity enough I was there before I knew about Heisenberg having been there, and discovered his version of QM.

And MigL, just for fun, Google 'Heisenberg Cocain', and you probably realise where the story comes from... It was good for a laugh at least.

Oh, and a fat +1 for Joigus, of course.

23 hours ago, joigus said:

You clarify the second point later, but I hope that doesn't mean 1) I cannot refer to quantum mechanics itself, in its closed mathematical form, in order to argue about what quantum mechanics itself means or implies. And 2) There's something about my statement of the EPR argument you don't agree with, but you reserve the right to bring it up later.

To 1). I completely accept what rolls out of the math of QM. I 'read' Leonard Susskind's Quantum Mechanics: The Theoretical Minimum, but somewhere halfway I had to give up on the math, but at least I can more or less follow the argumentation. Maybe I should now reread the relevant chapters again, with the present discussion in the back of my mind.

To 2): Ah, but I specified this immediate after that remark.

Your quote from Gell-Mann:

23 hours ago, joigus said:

"People say loosely, crudely, wrongly, that when you measure one of the photons it does something to the other one. It doesn't!! All that happens is you measure a property of one and you learn the corresponding property of the other one." 

But that is exactly what I think. Some years ago I had a thought exchange about this with Swansont. If I remember correctly, I defended that the only thing one can say something about is what the result of a measurement of the entangled partner will be. (Of course this is only valid when e.g. polarisers are in exactly the same position.) However, I am completely convinced that nothing physically changes. I think the reason I retracted to this point, is that there indeed are many descriptions of Bell-like experiments where is said something like "If the polarisation of one photon is measured, the other one immediately flips in the same direction." As if some 'Quantum God' already sees how the wave function changed,  before it is measured by a physical mortal. No, nothing flips, the only thing I can know for sure is what will be measured at the other end, if measured in the same polarisation direction.

Swansont and Gell-Mann (Swansont, correct me if necessary),and you make it already to 'reality' because under certain circumstances you can with 100% certainty predict what the other end will measure if the measurement is made with the same polarisers in the same direction. 

But I have to confess, now I am getting confused myself. Thinking about this I could imagine superluminal communication, so there should be an error in my thinking here. It is easy to determine if a beam of light is polarised: just turn a polarisation filter in the direction that lets through the maximum of light intensity, and you know its polarisation directon. Now do the same with entangled photons located exactly between Geneva (for obvious reasons) and the Andromeda galaxy. In Geneva I measure a small stream of photons, with a polariser at 0^o, and because the source of entangled photons is exactly in the middle, the entangled partner photons arrive there at the same time. The Andromedian measures in which direction they are polarised, and will also measure 0^o. So it does not work with single photons, but with many it would work. I assume I am making some huge error here, but at the moment I do not see where. My mind-overflow alert is blinking red... 

The one with the clearest explanation where my error lies, gets a free beer (entangled with the one I will drink then, so take care it does not spill over...).

I'll stop here for the moment, before my head explodes.

Never realised 'honest thinking' can hurt so much. Ah, how easier life would be if one could simply stick to an ideology!

Now I got confused in my reading myself: Bangstrom is saying that the 'connection' (whatever that may be) is not causal. I must add that we have to torture nature to the limit, to empirically observe these correlations.

18 hours ago, joigus said:

My only excuse is that I was pressed to answer to a rather "entangled" physical question in terms of quotes of famous people, a field in which I'm anything but confortable. I'd rather discuss things in terms of mathematical statements under premises that have passed the test of time, both because they've been analysed by many competent people --theorists and experimentalists alike--, and because they've passed the experimental tests themselves.

I understand that. For me however the mathematics of QM is a book with about 5 seals (if you know what I mean). What I am interested in is how physicists came to their hypotheses, and how these were empirically underpinned. (And of course the methodological and philosophical assumptions that go into these hypotheses). I always felt a bit disturbed by the lectures at university because physics was always presented as a ready made building. History of physics was one of my favourite subjects (and still is). And in my philosophy study, I was trained in reading (old) texts.

I notice a few ambiguities in your position. First you said:

On 9/21/2022 at 5:22 PM, joigus said:

Bell finally sets the record straight and publishes his famous paper on Bertlemann's socks and the nature of reality.

I took this as 'final statement of Bell in this matter', but you reacted on it as if you read 'final statement in this matter' (in general). And now you are saying:

18 hours ago, joigus said:

It is clear to me though that Bell --especially in his last years-- preferred to save locality and work instead on alternative extensions of quantum mechanics.

Wouldn't be 'final' in his last years?

Sorry for the ant fucking, but hey, I am a philosopher by education.  (Not profession...)

18 hours ago, joigus said:

Feynman and Gell-Mann, for example, shared the view that quantum correlations express nothing peculiarly non-local, but only carry with them a version of non-separability that's intrinsically quantum, and cannot be reproduced by any classical model.

What is non-separability when a spacelike distance is involved other than non-locality? (Beware: correlation, not causation.)

19 hours ago, joigus said:

Do you agree with my statement summarising the EPR argument?

More or less.

19 hours ago, joigus said:

If you can predict with absolute certainty the result of an experiment without in any way disturbing the system, there must be some element of reality underlying it.

"Some element", yes. But we have no idea what this element is.

Another problem I think I have is with:

19 hours ago, joigus said:

Either quantum mechanics is incomplete, or your wave function would have to be updated superluminally

As for me the wave function is not a physical object, there is nothing physically updated. The wave function is an idea, and there is no problem for ideas to be superluminal (now I think about the war in the Ukraine, and now I am thinking about the Andromeda galaxy. Wow, 2 million lightyears in less than a second!)

I know that the violations of Bell's inequalities roll out of the math of QM. You know the story that Feynman threw Clauser out of his office, because implicitly he was doubting QM? We know that QM predictions are empirically valid. But we don't know why. And my guess is we never will.

19 hours ago, MigL said:

I do have a problem with superluminal tranfer of information, and the definition Bangstrom has provided for 'non'locality' does just that.

I agree with that; however I am not so sure if it is Bangstrom's imprecise language (but he is not the only one guilty of that..). I however suppose that Bangstrom agrees that no information is transferred, and that the correlation between the remote measurements is not a causal relationship. @bangstrom: could you clarify, please, as precise as you can?

19 hours ago, MigL said:

Perhaps we are forgetting that we are dealing with models of the undelying reality, and while we can construct physical models of macroscopic processess and events, we are forever relegated to using only mathematical models of quantum processess and events.

I agree. But it is surprising that nature does something we can derive mathematically only, without knowing the ontological status of the wave function. I think I more or less agree with Bangstrom here:

11 hours ago, bangstrom said:

We are not just dealing with “models” we are dealing with actual physical experiments and the physical measurements describe events that defy our ‘common sense’ classical view of physicality. That doesn’t mean they are not real.

New word alert!

11 hours ago, bangstrom said:

The mathematics is used to describe what we are first observing with physical measurements of reproducible quantum experiments suggesting a non-local connection but not necessarily a communication.

Try to define these words, or try to say what you want to say without them.

11 hours ago, bangstrom said:

The main difference between QM and classical physics is that the classical physics requires a physical connection between a cause and effect while QM does not.

Nope. The correlation is not causal, as with the shoes in the boxes. The correlation however is stronger than we classically expect.

Hui, Joigus, now you have fallen into a trap. If it is your own, or the 'Journal de physique' (or some other source) I don't know, but Bell is citing Einstein in your highlighted passages:

Here Bell is speaking for himself:

And after his argument:

It is obvious that Bell doesn't like this conclusion, and discusses 4 ways out:

• QM is wrong, at least in the case of such situations
• Superdeterminism (he doesn't name it like that, but is clear that he is pointing at that)
• Lorentz transformations are not valid
• There is no reality below some "classical" "macroscopic" level (quotation marks from the original)

Concerning the first point: Aspect was still working on his experiments, and Bell refers to that. His comment:

We know how the experiment went out...

From other articles, I have reason to believe that he was going for the first point, i.e. that QM is incomplete. He was puzzled by the results of the Clauser and Aspect experiments.

Bell says exactly the opposite of what you are saying.

I think it is important that you all, discutants (my word creation?), are very clear with the words you are using. I give a few proposals:

1. action (or interaction): a physical process, where energy and momentum are exchanged, and so special relativity applies
2. correlation: as in the example of the shoes in the boxes

To 1: even Bell is confusing here, because he says "They cannot be explained, that is to say, without action at a distance." (Bold by me)

To 2: I would say that the Bell inequalities, together with the confirmation that they do not hold in QM in experiments, show that QM has stronger correlations than local realistic theories allow.

For me, I go with Bell's 4th 'way out', at least for now. The wave function is part of a calculation recipe. Why it works, we simply don't know. Why it leads to non-local correlations, we don't know either.  But the formalism of QM simply leads to the conclusion that non-local correlations are possible.

2 hours ago, joigus said:

One part of the problem is that J. S. Bell shifted his position somehow during the time that he was thinking about this problem. So it's not impossible that he said some things here and there that do not conform to what his final position was. So I'll do my best.

But I hope you remember what you said yourself:

23 hours ago, joigus said:

Bell finally sets the record straight and publishes his famous paper on Bertlemann's socks and the nature of reality. => You don't need any magical action at a distance to explain correlations based on a conservation principle. It happens classically all the time!

  Bold by me. Is it not finally then? 

2 hours ago, joigus said:

The final judge is, of couse, the experiment, and I'm sure nobody will ever by able to send any kind of superluminal signal.

Of couse. I agree, insofar if you mean with a superluminal signal that it implies a physical causal process (which implicitly would mean transfer of energy and momentum), and that people therefore could use for FTL communication. I think one problem (maybe also part of my problem) is the status of the wave function. My opinion: the wave function itself is not a physical object, so e.g. in Bell like experiments with spin, when Alice measures the spin from here side, there is changing nothing on Bob's side. (See the example of the gloves). The wave function is not a physical object*, which simply means that nothing changes because of Alice's measurement. This would then even be stronger than what I just said: there is no superluminal signal. But there is definitely some form of none-locality. But I would say this just rolls out of the formalism of QM, in the end the results of experiments like Aspect's and is followups are often described as 'QM was right again'.

* Therefore I cannot by in into the MWI.

2 hours ago, joigus said:

In my mathematically-biased mind, this is only too clear, as QM proposes nothing more than a finite-order differential equation, so unless this "model" is fundamentally wrong, no non-local effect can be claimed.

I understand that. QM is often called the best proven scientific theory we have. But we live in a classical world. And in this classical world it just looks like superluminal information transfer. A classical view must fail terribly. How should I imagine a wave function that is stretched over light years, and then collapses over its total length if we do a measurement at one of it's sides? Maybe that is the reason I like to declare the wave function as not-physical. It is part of a calculation recipe, not of nature. As a (dangerous?) analogy: the imaginary number i does also not represent any physical observation ('I walked 5i kilometers today'). But in our calculation recipes in e.g. QM, it plays an important role.

So, and now to cheer up the discussion a little, some pictures:

Bertlmann smells tea presented by John Bell.

Mermin and Bertlmann (yes, a few years later...)

Invitation for a talk by Bell in Vienna, with a student's addition.

I am getting more and more confused by this discussion. I wonder if there is a confusion of meanings of concepts you are using. E.g. could you all please be as precise as possible. ' What is Bell's theorem, and Aspect's experiment proving: that there are no local hidden variables, or even none-local variables? Just 'no hidden variables' is not clear enough.

17 hours ago, joigus said:

Bell finally sets the record straight and publishes his famous paper on Bertlemann's socks and the nature of reality. => You don't need any magical action at a distance to explain correlations based on a conservation principle. It happens classically all the time!

  I (tried to) read Bell's paper, and found following passage:

Quote

But we will argue that certain particular correlations, realizable according to quantum mechanics, are locally inexplicable. They cannot be explained, that is to say, without action at a distance.

Of course I am not happy with the expression 'action at a distance', (am i critising Bell? Ups...), where it is 'only' correlations we are talking about.

I think you (and I) all agree there is no action in the classical sense, i.e. some for of causation: this would imply FTL communication. And I (as I assume any other physicist) fully accept special relativity.

Another point I do not understand:

On 9/19/2022 at 6:21 PM, MigL said:

These fields are not local to the manifested particle.

<snip>

IOW, the wave equation is also global.

<snap>

The wave function, being a mathematical construct, collapses globally; there is no need for communication/interaction of any kind, sub-luminal or super-luminal.

  Since when is global local?

I agree with your last sentence, because we are talking correlation, not causation. There definitely is some none-local aspect in QM, as is said already a few times, because we cannot reproduce this phenomenon based on classical physics.

Further I am suspicious about two referenced articles (one by Joigus and one by MigL) that both base their argument on the MWI. MWI is a metaphysical stance, that heaves the wave function to real, physical existence. MigL's idea that it is just an interpretation, i.e. because (nearly) all QM-interpretations are empirical equivalent, its conclusions should be empirically equivalent seems not valid to me, because any kind of solution of Bell-like experiments is also an interpretation (super-luminal communication, super-determinism, etc). In my eyes, MWI is a nice way to wipe the problem under the carpet. Bohm also is an interpretation, and his quantum potential is definitely none-local.

And last but not least, Anton Zeilinger, in his Dance of the Photons: From Einstein to Quantum Teleportation, says it clearly: local realism is not a valid description of our world, i.e. either locality must be given up, or realism. The latter is also given as a potential way out in 'Bertlmann's socks':

Quote

Fourthly and finally, it may be that Bohr's intuition was right - in that there is no reality below some "classical" "macroscopic" level. Then fundamental physical theory would remain fundamentally vague, until concepts like "macroscopic" could be made sharper than they are today.

Addition: Funny fact:

I read the German version of Zeilinger's book, which was published by C. Bertelsmann... Not a perfect correlation, but close... 

Veritasium has Youtube videos about modern analogue computers. Maybe you should have a look?

2 hours ago, joigus said:

Good job!

Poor old late Einstein is falsely quoted more than anobody else in science, probably.

Careful: the citation did not seem 'einsteinian' to me, and I did not say he did not say it. I just did not find it with google. But that the only citation I found was in an article of 'Solomon' is highly suspicious.

Quote

'The problem with citations in the internet, is that you never know if somebody really said it'

A. Einstein

On 9/10/2022 at 3:29 PM, Bufofrog said:

Just out of curiosity does anyone (except the OP author) know what "The Problem" is?  I am a bit dense and I still haven't got an idea what "the Problem" is.

He mentioned it:

On 9/7/2022 at 9:52 PM, RSolomon said:

“The Problem” by Albert Einstein: “Which are the simplest formal structures that can be attributed to a four-dimensional continuum, and which are the simplest laws that may be constructed to govern these structures. We then look for the mathematical expressions of physical fields in these formal structures and the field laws of physics already known to a certain approximation from earlier research in simplest laws governing the structures.” 

It did not sound very 'einsteinian' to me, so I tried to google if I could find a reference that Einstein really said something the like.

I found exactly one reference... An article by a certain 'Solomon'...

If somebody has still has some curiosity left, he can look up everything there. It is the usual crackpotism.

On 9/8/2022 at 7:21 AM, RSolomon said:

(4.) I know what I need to know about Mr. Einstein

Obviously not.

On 9/8/2022 at 12:21 AM, studiot said:

Although he may well have been the world's greatest Physicist, he was no a Mathematician and had to rely on support form for competent mathematicians.

And your reaction:

On 9/8/2022 at 7:21 AM, RSolomon said:

(5.) Yes, Mileva was, in some real way, a great blessing.

I assume Studiot thought more about Marcel Grossmann and David Hilbert. Historians more or less agree that Mileva's role was mainly that of a highly intelligent 'resonance board'.

5 hours ago, chrisjones said:

perhaps we are not slaves to either free will or fate

'Slave of free will' is a contradiction.

Thanks, Markus, for your answer.

On 8/19/2022 at 11:03 PM, Markus Hanke said:

What they did was to approximate the tightly packed neutrons in a neutron star as a special kind of gas, called a Fermi gas. The dynamics of this were fairly well worked out, which made it possible to derive a rough limit for when neutron degeneracy is able to resist gravitation. It’s called the Oppenheimer-Volkoff limit

OK, looked it up. Seems that they had the order of magnitude correctly, but they seem to have come at a value that was even lower of that of a white dwarf. So still pretty rough, yes.

On 8/19/2022 at 11:03 PM, Markus Hanke said:

Yes, but if you keep collapsing the body, the pressures and energies will eventually get so high that the fundamental forces will re-unite into a GUT scenario - at which point the concept of ‘quark’ ceases to make sense.

But that is rather hypothetical too, isn't it? GUT is more a GUH (hypothesis) than a theory. AFAIK GUTs predict that the proton is not stable, but experiments already pushed the lifetime of the proton higher than predicted.

On 8/19/2022 at 11:33 PM, MigL said:

Speculation about quark stars don't make much sense to me, in light of the previous arguments, as they involve going to a much lighter fermion, and unphysical velocities again.

That's why I referred to a bottom/top quark star... Both are heavier than the proton. But I know this is 'extreme speculation'. And of course there would be a degeneration limit for them too.

18 hours ago, Markus Hanke said:

Since, once certain limits are exceeded, it is physically impossible to prevent gravitational collapse, these must contain singularities.

I assume you mean 'these must contain singularities according GR'. Which is the reason to say that, as is often said, 'GR breaks down' in the centre of a black hole.

What I am wondering is how Oppenheimer & co could be so sure about the 'total' gravitational collapse, without knowing all ins and outs of the strong nuclear force. How could they be sure, that gravitation would even overcome neutron degeneration? I mean even now, knowing that neutrons are made of quarks, the Pauli exclusion principle is also valid for quarks, in the end, these are also fermions. Maybe a '(top/bottom?) quark star' is hiding immediately behind the event horizon? How can we exclude such a scenario?

So I assume I am just asking 'which limits, and how do we know these limits?'.

1 hour ago, joigus said:

Einstein abhorred singularities

I think it is one step deeper. A black hole limits the knowability of science: it is principally impossible to have empirical knowledge of a black hole behind the event horizon, at least not in a way that it can become part of science (of course you possible could dive in a super-massive black hole without spaghettification, but you cannot come back to inform scientists about what you saw or measured...). My recent readings on the interpretation of QM seem to make a similar point for Einstein: he could not accept the 'spooky action at a distance'. For him there had to be some hidden variables that would explain it. Something has to be there, but that it is empirically outside our reach was not acceptable to him.