Can anti-realism really save nonlocality?

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Discussion Overview

The discussion revolves around the implications of realism and nonlocality in quantum mechanics, particularly in the context of quantum entanglement and measurement. Participants explore whether abandoning realism can eliminate the need for nonlocal explanations, referencing key figures such as Anton Zeilinger and Tim Maudlin, and examining various interpretations of quantum mechanics.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Technical explanation

Main Points Raised

  • Some participants note that Zeilinger's stance suggests that if objects lack well-defined properties before measurement, nonlocality may not be necessary to explain quantum entanglement.
  • Tim Maudlin argues that nonlocality is an empirical fact, independent of the realism debate, and that Bell's theorem supports this view.
  • One participant questions the assumption that the second particle's properties are determined immediately upon measuring the first, suggesting that its state may remain undetermined until measured.
  • Another participant emphasizes that quantum mechanics allows for correlations that cannot be explained by local classical theories, but does not permit superluminal interactions.
  • There is contention regarding the interpretation of quantum mechanics, with some asserting that it has always been non-realistic, while others argue that this view is merely one interpretation among many.
  • Participants discuss the implications of certainty in measurement outcomes, with some claiming that certainty implies realism, while others argue that this is interpretation-dependent.
  • One participant states that the mathematics of quantum mechanics indicates that measurement collapses the wave function, determining the outcome of the second measurement immediately after the first.
  • Another participant counters that the interpretation of measurement outcomes as "real" is not universally accepted across all interpretations of quantum mechanics.

Areas of Agreement / Disagreement

Participants express differing views on the relationship between realism and nonlocality, with no consensus reached. Some argue for the necessity of nonlocality in explaining entanglement, while others challenge this notion and propose alternative interpretations.

Contextual Notes

Limitations in the discussion include the reliance on various interpretations of quantum mechanics, which may affect the understanding of realism and nonlocality. The debate remains unresolved regarding the implications of measurement outcomes and the nature of properties before measurement.

  • #31
sahashmi said:
That’s why QM breaks relativity. We need a preferred frame
I think your problems with QM come from not understanding relativity.
 
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  • #32
martinbn said:
I think your problems with QM come from not understanding relativity.
There is no way to explain QM without breaking relativity.

A occurring before B and B occurring before A simultaneously violates logic. Both cannot be true. Something that is illogical can’t be true. And bell proved non locality to be true.

So either the first measurement influences the second or vice versa. Without an influence, there is no reason for independent stochastic random variables to be correlated to each other
 
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  • #33
lodbrok said:
The EPR definition of realism doesn't say the observed property is real. It says "there exists a physical property corresponding to the observed property"
Any examples of "observed property" that are not real by definition?
I mean, if an observed property exists, by definition it must be real, or not?
 
  • #34
sahashmi said:
A occurring before B and B occurring before A simultaneously violates logic. Both cannot be true.
Not understanding the simultaneity of relativity is the first sign that you have no understanding of relativity. That was my point.
 
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  • #35
martinbn said:
Not understanding the simultaneity of relativity is the first sign that you have no understanding of relativity. That was my point.
No, this has nothing to do with not understanding the simultaneity of relativity. I’m aware of what it says.

But you cannot explain QM with relativity intact. I’m saying that that relativity is wrong.

Relativity could simply be emergent and not fundamental, the same way Newtonian mechanics is wrong but its predictions still work. This principle has to be wrong because a) the correlations in QM cannot be explained otherwise and b) as a matter of logic, A occurring before B, and B occurring before A cannot both be true.
 
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  • #36
sahashmi said:
No, this has nothing to do with not understanding the simultaneity of relativity. I’m aware of what it says.

But you cannot explain QM with relativity intact. I’m saying that that relativity is wrong.

Relativity could simply be emergent and not fundamental, the same way Newtonian mechanics is wrong but its predictions still work. This principle has to be wrong because a) the correlations in QM cannot be explained otherwise and b) as a matter of logic,
This statement
sahashmi said:
A occurring before B, and B occurring before A cannot both be true.
is your own statement. If it isn't true, fine, but why do you blame it on relativity!
 
  • #37
martinbn said:
This statement

is your own statement. If it isn't true, fine, but why do you blame it on relativity!
Relativity says that in the case of entanglement, either the first measurement occurs before the other or vice versa, depending on the frame. I’m saying that this is impossible given the correlations that occur.
 
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  • #38
sahashmi said:
Relativity says that in the case of entanglement, either the first measurement occurs before the other or vice versa, depending on the frame. I’m saying that this is impossible given the correlations that occur.
QM and relativity are combined in QFT. There's no physical reason to abandon relativity. In that respect you are simply wrong.

One alternative is that nature is nonlocal. In the sense that it can manage correlations without FTL influences. You might not like that idea, but there is no reason to dismiss the idea.

I don't like the idea of MWI, for example. But, that doesn't mean I think it must be wrong.

QFT is a successful theory, so there is no reason to abandon it on philosophical grounds.
 
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  • #39
Thread closed for Moderation...
 
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  • #40
sahashmi said:
That’s why QM breaks relativity. We need a preferred frame

QFT, the most accurately verified theory we have, and basically at large distances, how nature must be (remember Wienberg's folk theorem), not only does not break relativity but is built on it. Special relativity, of course - general relativity is a whole new ball game.

Apologies to Berkeman; I did not notice the thread was closed. In my defence, the fact that QFT is built on special relativity is crucial.

Thanks
Bill
 
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  • #41
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