What is the explanation for quantum correlations?

[bremsstrahlung]

Does a valid experimentally verified scientific explanation exists for the phenomena of quantum entanglement?

Doesn't Quantum correlations demand explanations? What is the explanation for Quantum correlations? Is it,

1. Retro-causation
2. FTL
3. Information is finite and far more fundamental than matter.
4. Inter-connectedness outside of space-time.
5. Super-determinism

Do we then have to fall back on ‘no signaling faster than light’ as the expression of the fundamental causal structure of contemporary theoretical physics? That is hard for me to accept. For one thing we have lost the idea that correlations can be explained, or at least this idea awaits reformulation. More importantly, the ‘no signaling …’ notion rests on concepts that are desperately vague, or vaguely applicable. The assertion that ‘we cannot signal faster than light’ immediately provokes the question:


Who do we think we are?


We who make ‘measurements,’ we who can manipulate ‘external fields,’ we who can ‘signal’ at all, even if not faster than light. Do we include chemists, or only physicists, plants, or only animals, pocket calculators, or only mainframe computers? (Bell 1990, Sec. 6.12)

Yes, something is communicated superluminally when measurements are made upon systems characterized by an entangled state, but that something is information, and there is no Relativistic locality principle which constrains its velocity. There are many expressions of this point of view, an eloquent one being the following by Zeilinger:

The quantum state is exactly that representation of our knowledge of the complete situation which enables the maximal set of (probabilistic) predictions of any possible future observation. What comes new in quantum mechanics is that, instead of just listing the various experimental possibilities with the individual probabilities, we have to represent our knowledge of the situation by the quantum state using complex amplitudes. If we accept that the quantum state is no more than a representation of the information we have, then the spontaneous change of the state upon observation, the so-called collapse or reduction of the wave packet, is just a very natural consequence of the fact that, upon observation, our information changes and therefore we have to change our representation of the information, that is, the quantum state. (Zeilinger 1999, p. S291).

Doesn't the Schroedinger's cat thought experiment show the absurdity of the Copenhagen Interpretation?

Whenever a consistent correlation between such events is said to be understood, or to have nothing mysterious about it, the explanation offered always cites some link of causality.

Either one event causes the other or both events have a common cause. Until such a link has been discovered the mind cannot rest satisfied. Moreover, it cannot do so even if empirical rules for predicting future correlations are already known. A correlation between the tides and the motion of the moon was observed in antiquity, and rules were formulated for predicting future tides on the basis of past experience.

The tides could not be said to be understood, however, until Newton introduced his theory of universal gravitation. The need to explain observed correlations is so strong that a common cause is sometimes postulated even when there is no evidence for it beyond the correlation itself. (Bernard D'Espagnat)

What is the explanation for quantum correlations?

 

[bhobba]

Does a valid experimentally verified scientific explanation exists for the phenomena of quantum entanglement?

Of course it does. I and others have posted it many times.

So here we go again.

Entanglement is nothing mysterious, its simply an extension of the principle of superposition to different systems. Suppose two systems can be in state |a> and |b>. If system 1 is in state |a> and system 2 is in state |b> that is written as |a>|b>. If system 1 is in state |b> and system 2 is in state |a> that is written as |b>|a>. But we now apply the principle of superposition so that c1*|a>|b> + c2*|b>|a> is a possible state. The systems are entangled - neither system 1 or system 2 are in a definite state - its in a peculiar non-classical state the combined systems are in.

Because the only possible outcomes are |a>|b> or |b>|a> if you observe system 1 and get state |a> then you know system 2 is in state |b>, and similarly if you observe system 1 and get |b> you know system 2 is in state |a>. That's all entanglement is - a correlation. That's it, that's all. Let that sink in.

Imagine you have two slips of paper a red and a green one and put them in envelopes. Send one to the other side of universe and keep the other. Open the envelope and you see red - you immediately know the other is green, and conversely. Nothing weird or mysterious here. That's all that's going on with entanglement with a twist I will explain.

Now for the QM twist. It turns out the paper analogy is not quite the same as QM. The correlation is a bit different - its still just a correlation - but has statistical properties different to the paper example. Why the difference? The difference is in QM things do not have properties until observed to have them, whereas the slips of paper remain red or green at all times. But what if we insist it's like the slips of paper - then it turns out you need some kind of non local superluminal communication. That's really weird. But there is nothing compelling anyone to insist its like the slips of paper - simply accept QM allows a different kind of correlation and things are no longer mysterious.

There is nothing mysterious going on. QM explains exactly what's happening.

Thanks
Bill

 

[Weddgyr]

But there is nothing compelling anyone to insist its like the slips of paper - simply accept QM allows a different kind of correlation and things are no longer mysterious.

I would go farther and say that there is compelling evidence (Bell's Theorem + Aspect experiments) to insist that the slips of paper model be abandoned, but on the other hand I don't think there is any way to accept QM in a simple way. Whatever explanation is adopted for making the QM calculations invariably falls apart under closer scrutiny. There is a "just do the math" attitude but this inevitably ends up divorcing itself from physical context.

There is nothing mysterious going on. QM explains exactly what's happening.

QM predicts what will happen. I would contest that vanilla QM explains any of it in any satisfactory sense. I would point to the unresolved status of the interpretation of QM as evidence for this.

 

[Bruno81]

As bhobba pointed out, non-classical states exist in superpositions, meaning their inherent quantum uncertainty is spread out and shared(entangled) in the environment with all the other states in the universe. Upon measurement the states get their definite values hence the correlations which are always there due to their quantum nature. We don't notice these all encompassing quantum correlations because(enter favorite interpretation).

 

[zonde]

simply accept QM allows a different kind of correlation and things are no longer mysterious

"simply accept" does really belong in scientific explanation, at least if it is not backed up by scientific consensus that is reached after thorough investigation of the question.

 

[bhobba]

"simply accept" does really belong in scientific explanation, at least if it is not backed up by scientific consensus that is reached after thorough investigation of the question.

Simply accepting the consequences of a theory rather than making out there is more to it is very scientific.

Thanks
Bill

 

[bhobba]

I would go farther and say that there is compelling evidence (Bell's Theorem + Aspect experiments) to insist that the slips of paper model be abandoned,

Of course it has to be abandoned. If its like the slips of paper then there has to be FTL communication which doesn't happen with the paper slips.

The situation is simple - people make more complex than necessary - why - beats me.

Thanks
Bill

 

[zonde]

Doesn't Quantum correlations demand explanations? What is the explanation for Quantum correlations? Is it,

1. Retro-causation
2. FTL
3. Information is finite and far more fundamental than matter.
4. Inter-connectedness outside of space-time.
5. Super-determinism

Explanations are good when they can be tested experimentally. So far there seems to be no such explanation.
But from the five you named I would say that only 2. can be scientifically investigated.

As for now QM gives very reliable phenomenological description.

 

[bhobba]

Explanations are good when they can be tested experimentally. So far there seems to be no such explanation.

There is the explanation I gave and it can be and has been tested experimentally.

Thanks
Bill

 

[zonde]

Simply accepting the consequences of a theory rather than making out there is more to it is very scientific.

Agree.
But you propose to simply accept "different kind of correlation". To this I do not agree.

 

[Weddgyr]

Simply accepting the consequences of a theory rather than making out there is more to it is very scientific.

That attitude would have left Newton and contemporaries to accept Kepler's laws as they were and not bother investigating any deeper. More pertinently, it would have led the likes of Bohm and Bell and everyone else to accept the Copenhagen interpretation as it was, and we would never have different or new interpretations on this problem, or possibly even the magnetic moment of the electron if every part of the CI was internalized without question.

The correlations "cry out for explanation", and human beings collectively and scientists in particular will never be satisfied to accept them as they are. Where their quests for explanation will lead is another matter.

 

[bhobba]

Agree. But you propose to simply accept "different kind of correlation". To this I do not agree.

I propose accepting the logical consequences of a theory.

Thanks
Bill

 

[bhobba]

That attitude would have left Newton and contemporaries to accept Kepler's laws as they were and not bother investigating any deeper..

Newtons laws explained all that was then known as QM explains all that is now known.

Thanks
Bill

 

[zonde]

I propose accepting the logical consequences of a theory.

And now you are "making out there is more to it".

 

[bhobba]

And now you are "making out there is more to it".

Your logic escapes me.

Thanks
Bill

 

[ddd123]

"simply accept" does really belong in scientific explanation, at least if it is not backed up by scientific consensus that is reached after thorough investigation of the question.

This begs the question though. Suppose that our world was fully classical, we wouldn't even think of contesting the classical paradigm. No scientist before QM ever thought of contesting the classical paradigm: nobody said "we can't simply accept that our probability theory is this", or "we can't simply accept that statistical correlations behave like this". If I asked you why is this so, and the answer was "because that fit with our intuition while quantum mechanics doesn't", then you see that what is not scientific is this attitude of feeling comfortable with classical paradigms and unconfortable with quantum paradigms, it's just psychological bias.

 

[zonde]

This begs the question though. Suppose that our world was fully classical, we wouldn't even think of contesting the classical paradigm. No scientist before QM ever thought of contesting the classical paradigm: nobody said "we can't simply accept that our probability theory is this", or "we can't simply accept that statistical correlations behave like this". If I asked you why is this so, and the answer was "because that fit with our intuition while quantum mechanics doesn't", then you see that what is not scientific is this attitude of feeling comfortable with classical paradigms and unconfortable with quantum paradigms, it's just psychological bias.

Aren't "probability theory" and "statistical correlations" a math theories?

 

[zonde]

Your logic escapes me.

How is "different kind of correlation" a logical consequence of physics theory?

 

[bhobba]

Aren't "probability theory" and "statistical correlations" a math theories?

There is no such thing as a 'math theory' in physics ie just math and hence not real.

Applied probability is based on mapping events to the Kolmogorov axioms.

Thanks
Bill

 

[bhobba]

How is "different kind of correlation" a logical consequence of physics theory?

Take the statistical correlation of the slips of paper and the correlations of entangelement - they are different.

That's Bells Theorem.

Thanks
Bill

 

[zonde]

Take the statistical correlation of the slips of paper and the correlations of entangelement - they are different.

That's Bells Theorem.

So what? There is other kind of correlation that we know of. The kind of correlation that there can be between causally connected events is not ruled out by Bell's theorem.
Are QM correlations different from these as well that you want to introduce a new one?

 

[bhobba]

So what?

Bells inequality is testable and shows the correlations are different to the slips of paper.

Its irrelevant if they are further different kinds of correlations - if they exist - which I doubt.

Thanks
Bill

 

[bremsstrahlung]

Its irrelevant if they are further different kinds of correlations - if they exist - which I doubt.

Thanks
Bill

There are different kinds of correlations.

Quantum correlations without a causal order.

The logical consequence of Quantum theory is to redefine our preconceived notions of space-time but no progress has been made in that direction for decades. There is hardly a single theory which consistently and fully describes the physics of the small and also the physics of the large. When there is no consensus over whether the quantum state is real or not what logical consequence of the theory that I should simply accept?

 

[Nugatory]

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