Incompleteness of Bell's Theorems

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In summary: We don't yet have a complete description of quantum spacetime, so we can't say for certain that there is no non-locality.
  • #1
JPBenowitz
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It seems rather dubious to come to any conclusion of Bell's Theorem regarding Non-Locality without a complete description of quantum spacetime. The fundamental tenet of Non-Locality is that 'distant' physically isolated systems are correlated. However, distance is only well-defined in terms of a Metric Space. I argue that if we do not have a complete description of quantum spacetime then we do not have a suitable metric space to come to the conclusion that these physical systems are indeed 'distant'. This necessitates that quantum spacetime must have more structure than Minkowski spacetime. The apparent paradox associate with Bell's Theorems emerges from the implicit assumptions of the underlying topology of spacetime. Indeed it is possible that the correlation of these physical systems is fundamentally dictated by a much more rich topology on the Planck scale.
 
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  • #2
JPBenowitz said:
The apparent paradox associate with Bell's Theorems emerges from the implicit assumptions...

Where in Bell's proof of his theorem do you see such an assumption being used?
 
  • #3
Nugatory said:
Where in Bell's proof of his theorem do you see such an assumption being used?

I have no qualms with the proof itself but the conclusions drawn from it.
 
  • #4
Bell proved that either correlations can happen for no reason or there exists superluminal signals, which would violate causality. We have not experimentally found these superluminal signals and therefore until we do we assume that correlations can happen for no reason. My quarrel is that there is an implicit assumption of how information propagates in spacetime that is required to come to these conclusions. This implicit assumption is precisely the structure of quantum spacetime. For all we know this structure could be an entire network of quantum wormholes in which no superluminal signal is required.
 
  • #5
JPBenowitz said:
This necessitates that quantum spacetime must have more structure than Minkowski spacetime. The apparent paradox associate with Bell's Theorems emerges from the implicit assumptions of the underlying topology of spacetime.

Bell's notion of local causality does indeed assume a background classical Minkowski spacetime, or at least a background classical pseudo-Riemannian spacetime of known topology. The application of the Bell inequalities to infer that there is no theory obeying relativistic causality that can explain the correlations predicted by quantum mechanics is not affected by the possibility you raise, since we can define the predictions of quantum mechanics on such a spacetime. On the other hand, the application of the Bell inequalities to real experiments to infer that Nature itself is nonlocal may be affected by such considerations, where it is only one of many loopholes.
 
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  • #6
JPBenowitz said:
I have no qualms with the proof itself but the conclusions drawn from it.

The usual conclusion is: No physical theory of local Hidden Variables can ever reproduce all of the predictions of Quantum Mechanics.

What's problematic about that? If there are hidden variables, they cannot be local to the quantum object. Even with your hypothesis of spacetime, any hidden variables would not be considered local. Local meaning that only "nearby" (relative to c) influences can impact the outcome.

Also: please be aware that the state of the art in Bell tests has come a long way. It is possible to entangle particles that a) have never existed in each others' light cones; b) have never even existed at the same time; and c) are entangled AFTER they no longer exist. All of these situations are consistent with standard QM but inconsistent with many traditional views of either locality or realism.

So make of it what you will, we don't have a complete description of spacetime (maybe) or we don't have a complete description of "something" (not sure what). We simply know a "classical" perspective won't cut it. :-) That has to be good for something!
 
  • #7
The problem is the notion of what is considered "nearby" to the quantum object. The measure we use is a minkowski metric, which assumes that quantum spacetime is described by the same metric. I appreciate where Bell's tests have taken us insofar as we are capable of entangling particles that have never previously interacted. Although I do not see the meaningfulness of saying two particles that no longer exist can be entangled. What I am trying to say is that non-locality should be a consequence of the structure of quantum spacetime.
 

Related to Incompleteness of Bell's Theorems

1. What are Bell's Theorems and why are they important?

Bell's Theorems, also known as Bell's Inequalities, were proposed by physicist John Stewart Bell in the 1960s. They are a set of mathematical equations that describe the quantum mechanical phenomenon of entanglement and its implications for our understanding of reality. They are important because they challenge classical notions of causality and locality, and have been confirmed by numerous experiments.

2. What is the Incompleteness of Bell's Theorems?

The Incompleteness of Bell's Theorems refers to the fact that they do not provide a complete explanation of the phenomenon of entanglement. While they accurately describe the correlations between entangled particles, they do not fully explain how these correlations arise and why they violate classical notions of causality and locality.

3. How do Bell's Theorems relate to Einstein's theory of relativity?

Bell's Theorems and Einstein's theory of relativity are both attempts at understanding the fundamental nature of reality. While Einstein's theory focuses on the macroscopic world and the behavior of objects in space and time, Bell's Theorems delve into the microscopic world of particles and their interactions. However, both theories are limited in their ability to fully explain all aspects of reality, and there may be a need for a more comprehensive theory that combines the two.

4. Can Bell's Theorems be applied to all physical systems?

No, Bell's Theorems are specific to quantum mechanical systems and do not apply to classical systems. They also do not apply to systems that do not exhibit entanglement, as this phenomenon is a key requirement for the inequalities to be violated. Therefore, while Bell's Theorems are important in understanding certain aspects of reality, they do not provide a complete understanding of all physical systems.

5. How do Bell's Theorems impact our understanding of the universe?

Bell's Theorems have had a significant impact on our understanding of the universe. They have challenged classical notions of causality and locality, and have shown that there are fundamental limitations to our understanding of reality. They have also opened up new avenues of research and have led to the development of new theories, such as quantum mechanics and quantum field theory, which are essential for our understanding of the universe at a fundamental level.

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