Was Bell's hypothesis verified?

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In summary, the nonlocality theorem uses a linear combination of covariances to show that quantum mechanics is not a local realistic theory. This is demonstrated through the violation of Bell's inequality, which is derived from Bell's assumption of a locally realistic model for the EPR experiment.
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jk22
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The nonlocality theorem uses a linear combination of covariances :
##C(a,b)-C(b,c)+C(a,c)=\int A(a,s)B(b,s)-A(b,s)B(c,s)+A(a,s)B(c,s)ds##This uses the renaming of the parameter s. In a "Refutation of Bell's theorem" by Adenier, it is said that the parameter s should in fact be different in each covariance (due to the fact that classically s could represent the photon polarization and that it cannot be in 3 places at a time).

Was this checked by measuring experimentally by comparing the average of the product of the covariances ##\int ds A(a,s)B(b,s)A(b,s)B(c,s)A(a,s)B(c,s)ds##

##\int dsdtdu A(a,s)B(b,s)A(b,t)B(c,t)A(a,u)B(c,u)ds##
?
 
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jk22 said:
The nonlocality theorem uses a linear combination of covariances :
##C(a,b)-C(b,c)+C(a,c)=\int A(a,s)B(b,s)-A(b,s)B(c,s)+A(a,s)B(c,s)ds##This uses the renaming of the parameter s. In a "Refutation of Bell's theorem" by Adenier, it is said that the parameter s should in fact be different in each covariance (due to the fact that classically s could represent the photon polarization and that it cannot be in 3 places at a time).

That's just a crackpot response, it seems to me. Bell defines a pretty precise definition of what he means by a "local realistic theory", and the manipulations that result in his inequality follow from that definition. So their violation shows that quantum mechanics is not a local realistic theory. This suggestion that the hidden variable should be different in each covariance is just nonsensical.
 
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stevendaryl said:
That's just a crackpot response, it seems to me. Bell defines a pretty precise definition of what he means by a "local realistic theory", and the manipulations that result in his inequality follow from that definition. So their violation shows that quantum mechanics is not a local realistic theory. This suggestion that the hidden variable should be different in each covariance is just nonsensical.

Bell's assumed model for the EPR experiment is that you have two experimenters, Alice and Bob, and some source of twin pairs. For each twin pair, Alice chooses a detector orientation ##a## and Bob chooses a detector orientation ##b## and each performs a measurement that gives ##\pm 1##.

Bell assumes that for each twin pair produced, there is an associated parameter ##\lambda## and two associated functions ##A(a,\lambda)## and ##B(b,\lambda)## giving Alice's result and Bob's result, respectively.

From this model, if we assume that the parameter ##\lambda## has a probability distribution ##P(\lambda)##, then the correlation of Alice's and Bob's results will be given by:

* ##C(a,b) = \sum_\lambda P(\lambda) A(a, \lambda) B(b, \lambda)##

Bell's inequality follows mathematically from the expression *, which follows from his assumed locally realistic model.
 

1. What was Bell's hypothesis?

Bell's hypothesis, also known as Bell's theorem, states that the laws of quantum mechanics cannot be reconciled with the classical concept of locality, which assumes that physical properties are determined by nearby objects and not by distant ones.

2. How was Bell's hypothesis tested?

Bell's hypothesis was tested through an experiment known as the Bell test, which involved measuring the correlation between the spin of two entangled particles at different angles. If the results violated Bell's inequality, it would support the idea that quantum mechanics is non-local.

3. Was Bell's hypothesis verified?

Yes, Bell's hypothesis was verified through various experiments, including the Aspect experiment in 1982 and the Weihs experiment in 1998. These experiments showed that the results of the Bell test did indeed violate Bell's inequality, providing evidence for non-locality in quantum mechanics.

4. What are the implications of Bell's hypothesis being verified?

The verification of Bell's hypothesis has significant implications for our understanding of the fundamental nature of reality. It suggests that quantum entanglement, where particles can be connected and influenced by each other regardless of distance, is a real phenomenon and challenges the classical concept of locality.

5. Are there any criticisms of Bell's hypothesis?

Yes, there are some criticisms of Bell's hypothesis, including the possibility of loopholes in the experiments and the idea that there may be hidden variables that could explain the results without the need for non-locality. However, these criticisms have not been able to fully refute the evidence supporting Bell's hypothesis.

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