From: danforth@riacs.edu (Douglas G. Danforth)
Subject: Re: Hidden variable theories, was: Uncertainty Princi
Organization: RIACS, NASA Ames Research Center
Date: Thu, 10 Sep 92 19:29:09 GMT


]In article <1992Sep9.185040.18757@riacs.edu>, danforth@riacs.edu (Douglas G. Danforth) writes:
]
]> This assumes that Bell's theorem is a definitive and final answer.  For
]> inefficient detectors it is quite easy to construct a model which gives
]> the EXACT quantum mechanical two-particle correlations.  Bell's theorem
]> does not address this case of inefficient detectors.
]

paul says

]You need to distinguish between Bell's result and the experimental tests
]of it. Bell's theorem implies that quantum mechanics is not a local theory
]and suggests that this should be experimentally detectable. Bell's theorem
]does not address and is not affected by the many practical problems in
]conducting an experiment.

and again

]Any real experiment will always have some additional loopholes. Aspect
]was certainly aware that detector efficiency was an issue.
				   ^^^^^^^^^^^^^^^^^^^^^^^
Yes, I'm sure he was. Unfortunately, his 1982 experiment does not seem to
meet John Clauser's efficiency criterion nor the efficiency necessary to
invalidate my model.

]                                                           I do not
]completely follow your argument about efficiency. If you are saying that
]only those detections that confirmed violations of Bell's inequality were
]detected because of some unknown physical process, I agree that this is 
]possible. I am sure the experimenters were aware of this and classified
]it is another improbable but still possible loophole. 
]
]Paul Budnik

I am making a slight claim that there is a useful distinction between
"inefficiency" and "nondetection".  Inefficiency is quickly dismissed
(as you and others have done) as an artifact of the experimental design.
Nondetection goes a little deeper and asserts that photons can be in a state
which does not lead to their detection. The photon state plus the detector
state is what leads to this nondetection. It is neither just the photon nor
the detector separately but rather the collective state of the two. One can
assert that such nondetection is a fundamental physical process that needs to
be included in any discussion concerning Bell's theorem.

Without an explicit model, the previous statement may sound somewhat
mystical, however, I have an explicit model in mind. Rather than waste net
bandwidth stating the model (which was posted previously), let me ask some
plausible questions which could lead to nondetection: 45 degree incidence of
photons on bi-refringent crystal, which way does it go?  Resonance
conditions for triggering cascades in photo-multiplier tubes, phase?

Two degrees of freedom for the hidden variables are sufficient to construct
a model that capitalizes on nondetection to produce the QM and experimental
results (I am NOT claiming these degrees of freedom are polarization and
phase).  

It strikes me that the resolution of the issue of locality in quantum
mechanics must be of such a character that it is ubiquitous and obvious to
such an extent that it is has been overlooked. "Nondetection" has these
characteristics. Whether this is the resolution remains to be seen. I can
think of many arguments against it.

-- Doug Danforth

Xref: sparky sci.physics:14714 sci.math:11505