Violations of Bell Inequality imply nature is non-local?

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Do violations of Bell Inequality imply that nature is non-local?
Yes 100%  100%  [ 2 ]
No 0%  0%  [ 0 ]
Total votes : 2

Kon
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24 Feb 2013, 8:19 pm

I've posted this question on the physics forum and had quite a few responses. Some of the responses come from theoretical physicists that have published a number of papers in quantum foundations, but I'm still not absolutely certain about the two major sides of the debate although I do lean heavily to Bell's own position that violation of Bell's inequality implies non-locality irrespective of determinism, realism, counterfactuals, etc. But I'd like to see how people on this forum respond. For those interested in that thread you can see the voting and arguments and many references (see post 232-233) from various positions on this thread:

What do violations of Bell's inequalities tell us about nature?
http://www.physicsforums.com/showthread.php?t=670856

On this forum I'm going to limit the possible answers to only 2 choices:

Do violations of Bell Inequality imply that nature is non-local?
1. Yes. Violations of Bell's inequality implies nature is not non-local
2. No. Violations of Bell's do not necessarily imply non-locality (e.g. anti-realism, non-counterfactual, etc.)

I left out Superdeterminism because very few physicists take that view seriously because it kind of makes science a useless enterprise. As a summary here are quotes from prominent physicists taking each of the 2 positions:

1. Observed violations of Bell's inequalities implies that nature is non-local:

Quote:
In 1964, Bell proved that any serious version of quantum theory (regardless of whether or not it is based on microscopic realism) must violate locality. He showed that if nature is governed by the predictions of quantum theory, the "locality principle," precluding any sort of instantaneous (or superluminal) action-at-a-distance, is simply wrong, and our world is nonlocal.

Quote:
What is most relevant to Bell's Theorem is that the non-locality which it makes explicit in Quantum Mechanics is a small indication of pervasive ultramicroscopic nonlocality. If this conjecture is taken seriously, then the baffling tension between Quantum nonlocality and Relativistic locality is a clue to physics in the small.


2. Observed violations of Bell's inequalities do not imply non-locality
Quote:
...quantum measurement results do not preexist in any logically determined way before the act of measurement.

Quote:
...unperformed tests have no outcomes: it is wrong to try to account for the outcomes of all the tests you might have performed but didn’t.



graywyvern
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25 Feb 2013, 4:00 pm

this probably doesn't mean what it seems to mean.

we won't suddenly be able to teleport or telekinect just because our math gets a little squirrelly.
on the other hand, if it could start making us feel a little more connected to this world which is of us & not apart from us, that might be a good thing.
who knows, we might even become merciful, in time.


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ruveyn
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26 Feb 2013, 1:58 pm

graywyvern wrote:
this probably doesn't mean what it seems to mean.

we won't suddenly be able to teleport or telekinect just because our math gets a little squirrelly.
on the other hand, if it could start making us feel a little more connected to this world which is of us & not apart from us, that might be a good thing.
who knows, we might even become merciful, in time.


Quite right. The failure of the Bell inequalities does not give us an FTL Morse lamp.

ruveyn



Kon
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26 Feb 2013, 9:05 pm

As posted on the link (see my post 57), Norsen in his papers discusses why Bell felt that his theorem does tell us something about nature:

Quote:
Since all the crucial aspects of Bell’s formulation of locality are thus meaningful only relative to some candidate theory, it is perhaps puzzling how Bell thought we could say anything about the locally causal character of Nature. Wouldn’t the locality condition only allow us to assess the local character of candidate theories? How then did Bell think we could end up saying something interesting about Nature?...That is precisely the beauty of Bell’s theorem, which shows that no theory respecting the locality condition (no matter what other properties it may or may not have – e.g., hidden variables or only the non-hidden sort, deterministic or stochastic, particles or fields or both or neither, etc.) can agree with the empirically-verified QM predictions for certain types of experiment. That is (and leaving aside the various experimental loopholes), no locally causal theory in Bell’s sense can agree with experiment, can be empirically viable, can be true. Which means the true theory (whatever it might be) necessarily violates Bell’s locality condition. Nature is not locally causal.

Local Causality and Completeness: Bell vs. Jarrett
http://arxiv.org/pdf/0808.2178v1.pdf

With respect to a discussion of Bell's concept of local causality which is ruled out see this paper arguing once again why Bell's theorem does allow us to say something about nature:
Quote:
This of course raises the question of how we might go from recognizing the non-locality of some particular candidate theory, to the claim that nature is non-local. But this is just Bell’s theorem: all candidate theories which respect the locality condition are inconsistent with experiment. (See Section VI.) So the “one true theory” (whatever that turns out to be!) – and hence nature itself – must violate relativistic local causality.

J.S. Bell’s Concept of Local Causality
http://arxiv.org/pdf/0707.0401.pdf

graywyvern wrote:
this probably doesn't mean what it seems to mean. we won't suddenly be able to teleport or telekinect just because our math gets a little squirrelly.

I agree but it may be trying to tell us something about our present models as Bell writes:
Quote:
For me then this is the real problem with quantum theory: the apparently essential conflict between any sharp formulation [of quantum theory] and fundamental relativity. That is to say, we have an apparent incompatibility, at the deepest level, between the two fundamental pillars of contemporary theory...It may be that a real synthesis of quantum and relativity theories requires not just technical developments but radical conceptual renewal.