crowded quantum information

[joigus]

24 minutes ago, MigL said:

For their work in estabilishing that there is no local reality.

Exactly. They've experimentally proven the completely local non-reality of quantum mechanics.

[bangstrom]

17 hours ago, Eise said:

You should better take care of your words, which is very important in such fundamental questions. I made them italic:

• action: we had this again and again. There is no action, no interaction, no causal relationship, no information transfer, no affect, no influence between the measurements. These are all excluded by the no-communication theorem.

The no-communication theorem deals with FTL communication at the macro level but not at the quantum particle level. That is a different issue.

17 hours ago, Eise said:

change: there is no change, in the first place because a change needs a cause, and that is already done away with with the previous point. In the second place, we cannot detect this change, because we cannot observe the wave function itself. We cannot look deeper then individual quantum  measurements, and therefore we can only detect correlations.

We can’t observe the wave function but we can observe the changes that appear after the wave function is lost.

17 hours ago, Eise said:

On 10/7/2022 at 9:05 PM, bangstrom said:

This is the mainstream explanation again and you can take it or leave it, or better yet, look it up for yourself. It is easy to find.

This is hubris. Swansont knows more about QM than you, me, and Joigus together.

Swansont’s claims like those of joigus may be logical and consistent with the EPR effect but they are 50 years behind what we now understand about QM. The EPR effect was invalidated long ago by the Bell test and has been repeatedly invalidated ever since. Most notably by those who just won the Nobel.

The two are necromancing with the EPR and that is what I can't accept.

17 hours ago, Eise said:

21 hours ago, bangstrom said:

”The interesting point is that in the end we will, for Bob’s results, present a different interpretation depending on what Alice at a later time decides to do. She may decide to do a Bell-state measurement, or she might decide to do a measurement on each photon on its own, there is even an infinite zoo of possibilities in between. Depending on what Alice decides to do, the results registered earlier by Bob, the events that already happened, acquire a very different meaning."

Again you do not understand quite what Zeilinger is saying here, and his viewpoint later in the chapter. I italicized the words. Zeilinger does not talk about events 'influencing' events in the past. He is saying that our interpretation of the experiment is different. Alice's measurement occurring before Bob's measurements, or after his measurements are different experiments, i.e. we need different interpretations of the experimental situation.

Quote

 Agreed, it is interpretation- not influencing-  but that still that makes Alice an agent of change whether the experiment involves going forward or backward in time.

 

17 hours ago, Eise said:

You are referring to the mainstream again. And still, you are not able to mention any QM expert precisely arguing why it is that we have to give up locality in QM.

Locality still applies in QM but quantum entanglement is an exception.

Experts in any field rarely discuss the long established basics of their work so quotes from experts are hard to find. That job is left to the second tier experts and science journalists.

 

[joigus]

4 hours ago, bangstrom said:

The no-communication theorem deals with FTL communication at the macro level but not at the quantum particle level. That is a different issue.

This is not true. I think I was the first to mention the no-communication theorem. It deals with quantum-mechanical states. Period.

 

4 hours ago, bangstrom said:

Locality still applies in QM but quantum entanglement is an exception.

 

In the mathematical formalism of quantum mechanics, how do finite sums and products introduce non-locality?

IOW, how would the continuity equation be violated, how would the Lagrangian contain an unbounded order of spatial derivatives?

IOW, how would any coupling of any form relating \( \varphi_{1}\left( x \right) \) and \( \varphi_{2}\left( x+a \right) \) be justified in the Lagrangian, or the Hamiltonian?

Edited October 9, 2022 by joigus
minor correction

[bangstrom]

18 hours ago, MigL said:

Clauser, Aspect and Zeilinger were this year's recipients of the Nobel.
( see 'Science News' thread )

For their work in estabilishing that there is no local reality.

I would say we still have local reality for non-entangled particles but non-locality and instant action at a distance for entangled particles.

21 hours ago, joigus said:

For better or worse --for worse is more like it-- I will have to avoid resorting to mathematics. I will use pictures, plus reference to mathematical symbols. Are you OK with that?

I have no problem with your use of math and others might appreciate it. I have studied a lot of math but always found it difficult and tedious. I never had any use for it and I have largely repressed the experience.

21 hours ago, joigus said:

In words: "relativistic causality being violated does not imply non-locality.

Non-locality would be much, much, much, incommensurably much worse. And I'm telling you this knowing full well that relativistic causality is considered sacred by most physicists post-Einstein.

Perhaps non-locality is not implied, but non-locality is the best alternative and it works when needed.

 

21 hours ago, joigus said:

Non-locality would be much, much, much, incommensurably much worse. And I'm telling you this knowing full well that relativistic causality is considered sacred by most physicists post-Einstein.

It would imply that --in certain simple contexts-- you could make "something" instantly disappear "here," and at the same time appear "there."

If you accept this standard, we can go on.

Relativistic causality works in most instances but not for quantum entanglement. The violation of local realism and relativistic causality when non-local entanglement is involved leaves us with non-locality where a local change can instantly result in a change at a remote location. “Spooky action at a distance”.

21 hours ago, joigus said:

You may well ask: Is it the probability amplitude that's disappearing "here" and appearing "there" instantly? We can tackle that question if you want. 

21 hours ago, joigus said:

 

 Probability amplitudes may be the heart of the problem.

The violation of local realism and relativistic causality when non-local entanglement is involved leaves us non-locality where a local change can instantly result in a change at a remote location. “Spooky action at a distance”.

That is what happens with Zeilinger’s quantum teleportation except that it does not make anything disappear but it does make something instantly appear ‘over there’. The indeterminate state of an entangled particle instantly becomes determinate, but in this case it is not random, The quantum identity of the remote particle becomes identical to that of the particle inserted into the ‘teleporter’ to use a familiar but incorrect word.

For example, if you have two entangled particles AB and particle A is then sent far away to a remote location while B remains at home, then a second entangled pair CD can be created and particle C can be entangled with particle B so you have a three-way entanglement.

At Alice’s location   D-(CB) ----------------A   Bob’s location

If Alice observes the quantum state of particle D, the indeterminate properties (superposition) of all the particles instantly be determinate in a cascade of anti-correlated states. If D is +, C is -, B is +, and distant A is -. The observation of D is random and not fixed from the start. If Alice observed the quantum state of D as - , the entire cascade would be in reverse.

The thing to note here is that the later entanglement of C with B to create the entangled state (CB) makes (CB) a sort of ‘teleporter’ such the the quantum state of C also becomes the quantum state of A. To a naive observer of the events, it appears that particle C enters the (CB) ‘teleporter’ and instantly appears at the remote location A. This sort of identity swapping violates both local realism and relativistic causality which are based on macro level observations but they do not apply to what is observed with entangled particles.

We know from local reality that the Eiffel tower is in Paris and the leaning tower is in Pisa but in QM we never know which of an entangled particle is where until it is observed. Their ‘location’ is indeterminate and random until observed.

[Eise]

Sorry, @bangstrom, but now you crossed the border of an honest, argumentative discourse. I assume you have some ideological reasons, and that your ideology needs non-locality. Otherwise I cannot explain the huge misses you make here, and your derogation of Joigus' and Swansonts knowledge of QM.

3 hours ago, bangstrom said:

The no-communication theorem deals with FTL communication at the macro level but not at the quantum particle level. That is a different issue.

The no-communication theorem is derived from the formalism of QM, and is valid on all levels.

5 hours ago, bangstrom said:

We can’t observe the wave function but we can observe the changes that appear after the wave function is lost.

If you observe something only one time, you cannot conclude that it has changed. In Bell-like experiments, Bob from his side does not notice anything special. He just gets random results, as if he is just doing experiments on some simple particle source. Only when Alice and Bob compare their lists (these cannot be send FTL), they notice that the correlations are stronger than any classical system allows.

5 hours ago, bangstrom said:

Swansont’s claims like those of joigus may be logical and consistent with the EPR effect but they are 50 years behind what we now understand about QM.

On the contrary. The problem is you do not understand modern QM. Einstein objected against the non-local 'odour' of QM, but since then, physicists have developed QM further, and e.g. came up with the no-communication theorem, which excludes any FTL communication (and effect, and influence, and ...).

5 hours ago, bangstrom said:

The EPR effect was invalidated long ago by the Bell test and has been repeatedly invalidated ever since.

Invalidated? On the contrary, the conclusion of the article that seemed contradictory to relativity, was confirmed by Bell-like experiments: the QM depiction of the world that Einstein thought was too absurd to be true, turns out to be true.

5 hours ago, bangstrom said:

Most notably by those who just won the Nobel.

And still Zeilinger would rather give up realism than locality. That is clear if you would really read his book, understand his argumentation, instead of citing passages from his book that seem to support your position.

5 hours ago, bangstrom said:

Agreed, it is interpretation- not influencing-  but that still that makes Alice an agent of change whether the experiment involves going forward or backward in time.

Nope. Read, and understand what Zeilinger is saying: in short, if Alice does here measurement before or after Bob did, it describes two different experiments, which means different boundary conditions. As said before, of the five ways Zeilinger mentions that could explain Bell-like experiments, Zeilinger dismisses 'back in time propagation', instead refers, to the fact that they are different experiments. Maybe this has a connection, or is even an example of 'contextuality' as meant in the Kochen-Specker theorem? @joigus: do you  think that is correct?

5 hours ago, bangstrom said:

Experts in any field rarely discuss the long established basics of their work so quotes from experts are hard to find. That job is left to the second tier experts and science journalists.

So no outrage about the position of Gell-Mann, Susskind, Kracklauer, Sidney Coleman, etc.? In short, you are not able to show an authoritative text, that pleads for giving up locality instead of realism.

4 minutes ago, bangstrom said:

I would say we still have local reality for non-entangled particles but non-locality and instant action at a distance for entangled particles.

Sigh... Using 'action' again.

5 minutes ago, bangstrom said:

Perhaps non-locality is not implied, but non-locality is the best alternative and it works when needed.

'My experts' disagree with you, and Zeilinger explicitly prefers to give up on realism, instead of locality.

8 minutes ago, bangstrom said:

The thing to note here is that the later entanglement of C with B to create the entangled state (CB) makes (CB) a sort of ‘teleporter’ such the the quantum state of C also becomes the quantum state of A. To a naive observer of the events, it appears that particle C enters the (CB) ‘teleporter’ and instantly appears at the remote location A. This sort of identity swapping violates both local realism and relativistic causality which are based on macro level observations but they do not apply to what is observed with entangled particles.

I am afraid, you forgot again, that teleportation needs an additional classical communication channel.

I think I am done here. Unless a Bell-Kochen-Specker-Bangstrom inequality is derived that can distinguish if we must abandon locality, and not realism, (and empirically tested of course), I rest my case.

Your ideological glasses make you blind, blind as two perpendicular oriented polarisators behind each other.

 

 

[joigus]

1 hour ago, bangstrom said:

Probability amplitudes may be the heart of the problem.

Hold that thought, please. That is the heart and soul of the problem. I'm hoping by Hannukah/Christmas we will all be able to agree on a common ground. Where do classical data come from in the formalism of QM?

Bell's theorem --and its extensions-- tell us that if you want some "internal classical data, mutually-commuting hidden variables" to be able to hold the information that corresponds to the eigenvalues we later measure, all along, while the quantum state is propagating, they would have to implement that non-locally.

So what happens when we actually perform a measurement? The environment-chosen, einselected in Zurek's parlance, data have to be implemented in the quantum state in a way that's nothing to do with QM (the Schrödinger equation.) That would be non-local. That's what quantum-teleportation people call "classical data." So, when you say,

1 hour ago, bangstrom said:

except that it does not make anything disappear but it does make something instantly appear ‘over there’.

You got it backwards. It's the components of the quantum state that have been experimentally discarded that must die now => They non-locally disappear. They must magically slip out of existence. Schematically:

Because you can never measure anything concerning something that --following Copenhagen's old-school-- slipped out of existence, and because your fancy-schmancy quantum state was never an observable in the first place. How can you tell?

This cross-out red scribble is all there is to your "non-local interaction." Of course, there's presumably nothing of the kind.

1 hour ago, Eise said:

Maybe this has a connection, or is even an example of 'contextuality' as meant in the Kochen-Specker theorem? @joigus: do you  think that is correct?

I must acknoledge I'm confused by the word "contextual" in KS-theorem. I will have to take a deeper look at that, and your help will be much appreciated.

What I know about it is that, for dim > 2 in space of quantum systems, you can actually build 3 mutually commuting operators --thereby compatible observables--, such that their expected values constitute an algebra closed under addition and multiplication:

<ABC> = <A><B><C>

<A+B+C> = <A>+<B>+<C>

From this critical dimension of 3 upwards, you cannot obtain these averages over commuting (classical, sharply-defined, yes-no, etc) hidden variables: A(v), B(v), C(v).

How that tells you something about the context, your guess is as good as mine. I tend to see it as "ontological."

You cannot obtain them except for certain judicious choices of A, B, C, that is. Bell's flavour all over it.

Edited October 9, 2022 by joigus
minor correction

[MigL]

While Bangstrom continues to assume some sort of magical 'interaction' that does not involve any interaction, Eise has neatly summed up exactly what happens ...

2 hours ago, Eise said:

If you observe something only one time, you cannot conclude that it has changed. In Bell-like experiments, Bob from his side does not notice anything special. He just gets random results, as if he is just doing experiments on some simple particle source. Only when Alice and Bob compare their lists (these cannot be send FTL), they notice that the correlations are stronger than any classical system allows.

It is almost like there is no reality between measurements ( only probability amplitudes ).
IOW,  No ( ocal ) reality =/=> Non-local reality.

Edited October 9, 2022 by MigL

[joigus]

1 hour ago, MigL said:

While Bangstrom continues to assume some sort of magical 'interaction' that does not involve any interaction, Eise has neatly summed up exactly what happens ...

It is almost like there is no reality between measurements ( only probability amplitudes ).
IOW,  No ( ocal ) reality =/=> Non-local reality.

Referring to,

4 hours ago, Eise said:

If you observe something only one time, you cannot conclude that it has changed. In Bell-like experiments, Bob from his side does not notice anything special. He just gets random results, as if he is just doing experiments on some simple particle source. Only when Alice and Bob compare their lists (these cannot be send FTL), they notice that the correlations are stronger than any classical system allows.

9 hours ago, bangstrom said:

(My emphasis on both.) Thank you:

On 9/21/2022 at 1:54 AM, joigus said:

Mind you: Decoherence tells you that the different components of the wave function are no longer in phase --think about the double-slit experiment. How do you measure that with just one instance? How do you know there is no longer interference by shooting just one electron?

On 9/21/2022 at 12:25 AM, Mitcher said:

It's so nice to have such attentive and deep-thinking readers on this thread.

I'll let @Eise, @swansont and yourself (+1) do all the conceptual clearing up from now on, as long as the point gets across. My word, you folks really are no-nonsense thinkers.

I'll gladly accept the humble role of "finessing up" the points to make them more and more obscure, which is

my thing, from the looks of it.  

[bangstrom]

17 hours ago, Eise said:

If you observe something only one time, you cannot conclude that it has changed. In Bell-like experiments, Bob from his side does not notice anything special. He just gets random results, as if he is just doing experiments on some simple particle source. Only when Alice and Bob compare their lists (these cannot be send FTL), they notice that the correlations are stronger than any classical system allows.

In one observation, we can know that one quantum property of particle B, has gone from indeterminate to determinate.

If you have two entangled electrons A and B, the first observation is random, spin-up or spin-down, and the quantum properties of both electrons are indeterminate (superimposed). If particle A is observed first as spin-up that simultaneously and non-locally fixes the spin of particle B as spin down. With repeated experiments we can determine that the observation of particle B has also gone from random to fixed by the observation of electron A and the loss of entanglement..

The FTL nature of the transaction can not be discovered until a later analysis of the timing has been made. That doesn’t mean that there was no FTL transaction between the particles just because we can’t observe it as FTL until a later time.

17 hours ago, Eise said:

On the contrary. The problem is you do not understand modern QM. Einstein objected against the non-local 'odour' of QM, but since then, physicists have developed QM further, and e.g. came up with the no-communication theorem, which excludes any FTL communication (and effect, and influence, and ...).

The no-communication theorem says you can not clone quantum properties but you can ‘clone’ or copy a single property but not all so QM allows for more probabilities than the classical model. I see Bell’s explanation as similar to the coin toss example. In the classical view, a coin can be heads on one side and tails on the other. It can also be heads green and tails red. So, if the heads side is is up, the green side is up also.  

The Bell test rules out the classical model because it allows for more probabilities than the classical model. A coin colored red and green can land heads-red or heads-green or tails-red and tails-green. In QM, each quantum property is random when observed and not necessarily fixed from the start or directly connected with all the other properties.

Also, Einstein died in 1955 roughly a decade before Bell and Aspect' experiments invalidated the EPR effect so Einstein's view and the EPR do not serve as guides for understanding modern QM.

18 hours ago, Eise said:

I am afraid, you forgot again, that teleportation needs an additional classical communication channel.

This is exactly like the old saying, ‘It hasn’t happened until it is reported on TV.’ The classical communication channel needs non-local teleportation to come first or there would nothing to observe.

18 hours ago, Eise said:

Invalidated? On the contrary, the conclusion of the article that seemed contradictory to relativity, was confirmed by Bell-like experiments: the QM depiction of the world that Einstein thought was too absurd to be true, turns out to be true.

Invalidated? Yes, the EPR effect certainly was invalidated.

The EPR effect was Einstein et al.’s hypothesis and the EPR was invalidated by experiments involving the Bell test. The EPR was Einstein’s objection to non-locality- “Spooky action at a distance”. 

So what you said is true but contrary to your claim, “The QM depiction of the world that Einstein thought was too absurd to be true, turns out to be true.” Einstein and his EPR effect with no “Spooky action” were demonstrated as wrong and non-locality that Einstein found absurd was demonstrated to be true.

In Zeilinger’s book ‘Dancing’ chapter “Atomic Sources of Entanglement and Early Experiments”,

Zeilinger said, “The results of Clauser and Freedman’s experiment, published in 1972 , clearly showed that Bell’s inequality was violated. The world is nonlocal, concluded most physicists. But that, as we discussed already, is not the only possible interpretation.”

He goes on the mention an experiment at Harvard that showed there was no violation of Bell’s inequality. Clauser later repeated the experiment hoping to demonstrate that local realism was valid but his results demonstrated that the Harvard experiment was in error and local realism was indeed violated.

Zeilinger then goes on to explain how later more precise experiments confirmed that local realism was violated confirming non-locality. So the EPR effect was violated, dead and buried.

18 hours ago, Eise said:

And still Zeilinger would rather give up realism than locality. That is clear if you would really read his book, understand his argumentation, instead of citing passages from his book that seem to support your position

Realism and locality are parts of the same thing. Zeilinger gave up local realism and locality and accepted the existence of non-locality.

Quoting passages serves two purposes. It allows me to reexamine my personal views to see if they actually conform to what I think author says and it allows the reader to do the same and clear up any misconceptions that may arise. I find that better than the practice frequently used here of repeating unsupported personal opinions as if they were fact. That only means you have an opinion.

In Zeilinger’s book ‘Dancing’ chapter “Atomic Sources of Entanglement and Early Experiments”,

Zeilinger said, “The results of Clauser and Freedman’s experiment, published in 1972 , clearly showed that Bell’s inequality was violated. The world is nonlocal, concluded most physicists. But that, as we discussed already, is not the only possible interpretation.”

He goes on the mention an experiment at Harvard that showed there was no violation of Bell’s inequality. Clauser later repeated hoping to demonstrate that local realism was valid but his results demonstrated that the Harvard experiment was in error and local realism was indeed violated.

That is Zeilinger’s argumentation for non-locality.

18 hours ago, Eise said:

18 hours ago, bangstrom said:

I would say we still have local reality for non-entangled particles but non-locality and instant action at a distance for entangled particles.

Sigh... Using 'action' again.

"Action" was Einstein's word and often repeated by others. It has become a well understood cliché

.

 

16 hours ago, MigL said:

While Bangstrom continues to assume some sort of magical 'interaction' that does not involve any interaction, Eise has neatly summed up exactly what happens ...

It is almost like there is no reality between measurements ( only probability amplitudes ).
IOW,  No ( ocal ) reality =/=> Non-local reality.

Einstein et al. found non-local interaction at a distance too absurd to be true but the experiments of Aspect Clauser and others demonstrated it's reality. That was fifty years ago so it should not be news to anyone.

[joigus]

49 minutes ago, bangstrom said:

If you have two entangled electrons A and B, the first observation is random, spin-up or spin-down, and the quantum properties of both electrons are indeterminate (superimposed). If particle A is observed first as spin-up that simultaneously and non-locally fixes the spin of particle B as spin down. With repeated experiments we can determine that the observation of particle B has also gone from random to fixed by the observation of electron A and the loss of entanglement..

Here's the sloppiness and ambiguous language again.

54 minutes ago, bangstrom said:

the first observation is random

The observation is not random, it's a choice.

The outcome is random. Now, "random" doesn't mean anything much. What kind of "random"? What probability distribution?:

The average is zero. =0

The dispersion is maximal. = 1/2 (equally likely to get +1/2 or -1/2.)

OK?

56 minutes ago, bangstrom said:

If particle A is observed first as spin-up that simultaneously and non-locally fixes the spin of particle B as spin down.

This is called begging the question. I could let you off with a warning but, hey. No.

Start again, please.

 

[Eise]

Wrong again:

2 hours ago, bangstrom said:

The no-communication theorem says you can not clone quantum properties

The no-clone theorem and the no-communication theorem are two different results derived from QM.

2 hours ago, bangstrom said:

Zeilinger then goes on to explain how later more precise experiments confirmed that local realism was violated confirming non-locality.

Nope. Yes, he says that local realism is violated, but as MigL already said (and Joigus, and Zeilinger) that means that either:

• locality is violated, or
• realism is violated,
• or both of course.

Zeilinger tends to giving up on realism.

That's it. I won't react on all your other concept- and word bending misinterpretations. Learn reading, and then QM.

I forgot this one:

2 hours ago, bangstrom said:

Quoting passages serves two purposes. It allows me to reexamine my personal views to see if they actually conform to what I think author says

What you are really doing is picking citations, that confirm your pre-existing belief, out of context without understanding the overall argumentation.

Edited October 10, 2022 by Eise

[bangstrom]

2 hours ago, joigus said:

This is called begging the question. I could let you off with a warning but, hey. No.

Start again, please.

 The question is below:

 

22 hours ago, Eise said:

If you observe something only one time, you cannot conclude that it has changed. In Bell-like experiments, Bob from his side does not notice anything special. He just gets random results, as if he is just doing experiments on some simple particle source. Only when Alice and Bob compare their lists (these cannot be send FTL), they notice that the correlations are stronger than any classical system allows.

And my answer was below. What is the problem?

 

3 hours ago, bangstrom said:

In one observation, we can know that one quantum property of particle B, has gone from indeterminate to determinate.

 

1 hour ago, Eise said:

4 hours ago, bangstrom said:

Zeilinger then goes on to explain how later more precise experiments confirmed that local realism was violated confirming non-locality.

Nope. Yes, he says that local realism is violated, but as MigL already said (and Joigus, and Zeilinger) that means that either:

• locality is violated, or
• realism is violated,
• or both of course.

Zeilinger tends to giving up on realism.

That's it. I won't react on all your other concept- and word bending misinterpretations. Learn reading, and then QM.

He abandoned realism only and not locality for entanglement as well?

I don’t read so good so can you explain what this means with no big words?

“Nearly all physicists agree that the experiments have shown that local realism is an untenable position. The viewpoint of most physicists is that the violation of Bell’s inequality shows us that quantum mechanics is nonlocal. This nonlocality is exactly what Albert Einstein called “spooky’; it seems eerie that the act of measuring one particle could instantly influence the other one.”

Anton Zeilinger “Dance of the Photons” p. 286 chapter “What could it all Mean ?”

[joigus]

47 minutes ago, bangstrom said:

The question is below:

No. Your statement is logically fallacious:

https://en.wikipedia.org/wiki/Begging_the_question

Sorry, I thought you knew what "begging the question" means.

It means you're asking to concede precisely the point that is under scrutiny.

Example:

Freedom of the press is one of the most important hallmarks of a modern, open society because modern, open societies value the ability of the press to report what’s happening.

 

I hope it's clear why your misunderstanding of "begging the question" makes this discussion very difficult. If you're allowed to stick to one word, and you claim the right to repeat its use by decoupling it into different wordings of it, loosely synonymous, then it's never gonna end. Once your premises are stripped to their bare minimum, you will be going like this:

I meant by non-locality what I meant by non-locality. Why? Quantum non-locality. That's the one I mean.

And by "interaction" I mean what I mean by "interaction."

Not a satisfactory logical posture, is it?

[Eise]

5 hours ago, bangstrom said:

In one observation, we can know that one quantum property of particle B, has gone from indeterminate to determinate.

But nothing on Bob's side shows him that the particle has an entangled partner.

OK, if you really need reading help, I am not such a bad guy.

- - - - - - 

1 hour ago, bangstrom said:

Nearly all physicists agree that the experiments have shown that local realism is an untenable position

Nearly all physicists agree that the experiments have shown that either locality or realism, or both, must be given up.

1 hour ago, bangstrom said:

The viewpoint of most physicists is that the violation of Bell’s inequality shows us that quantum mechanics is nonlocal.

Most physicists think that we must give up on locality.

1 hour ago, bangstrom said:

This nonlocality is exactly what Albert Einstein called “spooky’; it seems eerie that the act of measuring one particle could instantly influence the other one.

That is exactly what Einstein meant, and called 'spooky'. It seems weird that when one measures one particle, it immediately influences the other one.

- - - - - - 

But take care!  In the next paragraph, Zeilinger speaks for himself, not for 'most physicists'. And there he clearly says, that he thinks we should drop realism, not locality.

Edited October 10, 2022 by Eise

[joigus]

7 minutes ago, Eise said:

But take care!  In the next paragraph, Zeilinger speaks for himself, not for 'most physicists'. And there he clearly says, that he thinks we should drop realism, not locality.

Exactly. Zeilinger is pointing to a widespread confusion.

8 minutes ago, Eise said:

That is exactly what Einstein meant, and called 'spooky'. It seems weird that when one measures one particle, it immediately influences the other one.

Zeilinger's choice of words is "eerie." Clear symptom that he's not enamoured of the idea.

I must say that, even today, some physicists dare not speak out about this, or very openly at all, and choose to sprinkle their language with words like "somehow," "seems like," "said to be," etc.

[bangstrom]

11 hours ago, bangstrom said:

On 10/9/2022 at 6:18 AM, Eise said:

If you observe something only one time, you cannot conclude that it has changed. In Bell-like experiments, Bob from his side does not notice anything special. He just gets random results, as if he is just doing experiments on some simple particle source. Only when Alice and Bob compare their lists (these cannot be send FTL), they notice that the correlations are stronger than any classical system allows.

The first part reads,“If you observe something only one time, you cannot conclude that it has changed. In Bell-like experiments, Bob from his side does not notice anything special. He just gets random results, as if he is just doing experiments on some simple particle source. “

OK, and I could add that neither Bob nor Alice notice anything special. Also this is a Bell-like experiment with entangled particles going one to Bob and the other to Alice.

The last sentence reads,“Only when Alice and Bob compare their lists (these cannot be send FTL), they notice that the correlations are stronger than any classical system allows.”

This is when the signal becomes determinate on Bob’s end and both Alice and Bob notice that their observations are anti-correlated in the after analysis. This can be repeated numerous times to verify that the anti-correlation was not by chance.

Suppose that Bob reads his signal before any ‘light speed’ signal could reach his location, his signal should still always be anti-correlated with that of Alice suggesting that their signals were superluminal contrary to the classical view. Nicht wahr?

 

 

 

[swansont]

2 hours ago, bangstrom said:

Suppose that Bob reads his signal before any ‘light speed’ signal could reach his location, his signal should still always be anti-correlated with that of Alice suggesting that their signals were superluminal contrary to the classical view.

How can Bob read a signal before it gets to him?

[bangstrom]

1 hour ago, swansont said:

 

1 hour ago, swansont said:

How can Bob read a signal before it gets to him?

The loss of entanglement is instant on both ends so both particles decohere and become determinate simultaneously. This is the observation made on both ends. We know from SR that two any two points separated by space are separated by time at the rate of one second for every for every 300,000 km of distance. The timing of events is space-like, "Spooky action at a distance." aka 'non-local' but Alice and Bob have no way of knowing this until they can compare notes later about the timing on both ends. This is why entanglement can not be used for for FTL signaling.

[swansont]

2 minutes ago, bangstrom said:

The loss of entanglement is instant on both ends so both particles decohere and become determinate simultaneously. This is the observation made on both ends. We know from SR that two any two points separated by space are separated by time at the rate of one second for every for every 300,000 km of distance. The timing of events is space-like, "Spooky action at a distance." aka 'non-local' but Alice and Bob have no way of knowing this until they can compare notes later about the timing on both ends. This is why entanglement can not be used for for FTL signaling.

Can you answer the question now?

You acknowledge that the signal between Alice and Bob travels no faster than c.

But previously you said there was another signal that Bob reads prior to that. What is that signal?

[joigus]

57 minutes ago, bangstrom said:

The loss of entanglement is instant on both ends so both particles decohere and become determinate simultaneously. This is the observation made on both ends. We know from SR that two any two points separated by space are separated by time at the rate of one second for every for every 300,000 km of distance. The timing of events is space-like, "Spooky action at a distance." aka 'non-local' but Alice and Bob have no way of knowing this until they can compare notes later about the timing on both ends. This is why entanglement can not be used for for FTL signaling.

So you're proposing they do, what, 100000? sequential measurements, to check that particle after particle that were, what, 500 miles away of each other?... are "decohering" with each other(!!!???) so there is no interference pattern? What are you measuring that decoherence against? After many hours have passed you conclude every time something instantaneous must have happened every single time?

Decoherence can be checked for components of the wave function that hit on pretty mutually close spots of a screen. It's a property of collectivities of particles, not of pairs of particles.

How do you check 500-mile-away wave functions must have decohered?

How do you prove interfering patterns are lost between things that are, by now, 500 miles away?

You clearly don't understand what decoherence is about. Particles don't decohere with each other. That makes no sense. The quantum state decoheres with itself, like in the double-slit experiment. The statistics of many experiments tell you that.

[bangstrom]

1 hour ago, swansont said:

Can you answer the question now?

You acknowledge that the signal between Alice and Bob travels no faster than c.

But previously you said there was another signal that Bob reads prior to that. What is that signal?

The first signal amounted to a single qubit of non-local, quantum information that established the identity of Bob's particle as anti-correlated to Alice's particle. The second communication could have been by snail mail but, if it included accurate information about the timing of events, it should identify the timing of the first signal as superluminal.

Bell, Aspect and Clauser won the Nobel prize for demonstrating that the first signal was both not fixed from the start and also that it was superluminal.

[swansont]

19 minutes ago, bangstrom said:

The first signal amounted to a single qubit of non-local, quantum information that established the identity of Bob's particle as anti-correlated to Alice's particle.

What interaction is used to send this qubit? Electromagnetic and gravitational are limited to c.

Will you ever answer this question?

 

[bangstrom]

48 minutes ago, joigus said:

So you're proposing they do, what, 100000? sequential measurements, to check that particle after particle that were, what, 500 miles away of each other?... are "decohering" with each other(!!!???) so there is no interference pattern? What are you measuring that decoherence against? After many hours have passed you conclude every time something instantaneous must have happened every single time?

Decoherence can be checked for components of the wave function that hit on pretty mutually close spots of a screen. It's a property of collectivities of particles, not of pairs of particles.

How do you check 500-mile-away wave functions must have decohered?

How do you prove interfering patterns are lost between things that are, by now, 500 miles away?

You clearly don't understand what decoherence is about. Particles don't decohere with each other. That makes no sense. The quantum state decoheres with itself, like in the double-slit experiment. The statistics of many experiments tell you that.

The presence of an interference pattern suggests the presence of a two way, non-local, wavelike connection between the signal and receiver prior to an energy transfer.

Decoherence is simply the loss of a previous connection and an interference pattern indicates some kind of a previous connection. Instantaneous every time.

No doubt an interference pattern is a collective property when more than two particles are involved.

The possibility of interference is not lost over distance.

Naturally, the quantum state comes and goes. It adheres and deconheres.

[joigus]

7 minutes ago, bangstrom said:

The presence of an interference pattern suggests the presence of a two way, non-local, wavelike connection between the signal and receiver prior to an energy transfer.

 

Wrong.

7 minutes ago, bangstrom said:

Decoherence is simply the loss of a previous connection and an interference pattern indicates some kind of a previous connection. Instantaneous every time.

Wrong.

9 minutes ago, bangstrom said:

No doubt an interference pattern is a collective property when more than two particles are involved.

 

Obscure at the very least. Not very meaningful.

10 minutes ago, bangstrom said:

Naturally, the quantum state comes and goes. It adheres and deconheres.

Totally meaningless.

Could you, at least, answer Swansont's question, please?

24 minutes ago, swansont said:

What interaction is used to send this qubit? Electromagnetic and gravitational are limited to c.

Will you ever answer this question?

 

[bangstrom]

16 minutes ago, swansont said:

What interaction is used to send this qubit? Electromagnetic and gravitational are limited to c.

Will you ever answer this question?

 

It isn't EM or limited to c and it is prior to an EM exchange of energy. John Cramer calls it a transaction between advance and retarded waves between a signal and receiver or quantum 'handshake'. Wheeler and Feynman had the same idea with similar names as have other theories but they all agree that it is a direct interaction between a signal and receiver.