Newsgroups: sci.physics
Subject: Re: Hidden variable theories, was: Uncertainty Princi
From: campo@sunthpi3.difi.unipi.it (Massimo Campostrini)
Date: 8 Sep 92 14:45:54 +0100
Reply-To: campo@sunthpi3.difi.unipi.it
Distribution: world
Organization: Istituto Nazionale di Fisica Nucleare, Pisa, Italy

In article <265@mtnmath.UUCP>, paul@mtnmath.UUCP (Paul Budnik) writes:
|> In article <1992Sep7.001518.525@prim>, prim!dave@germany.eu.net (Dave Griffiths) writes:
|>
[good discussion about hidden variables deleted] 
|> 
|> In a paper written later but published first Bell did just that. He showed
|> that quantum mechanics is not a local theory. There are experimentally
|> observable effects predicted by quantum mechanics that involve instantaneous
|> action at a distance. This result says *nothing* about the completeness of
|> quantum mechanics. It simply implys that any theory that is consistent with
|> quantum mechanics must be nonlocal.
|> 

  To be precise, any "hidden variables"-type theory consistent with
quantum mechanics must be nonlocal. Quantum electrodynamics and other
relativistic quantum field theories are local, according to any
reasonable definition of locality. (I agree that locality of
non-relativistic quantum mechanics is debatable.)

[experimental situation etc. deleted]
|>
|> Current theory predicts that vast quantities of information are being
|> transmitted instantaneously over billions of light years. Eberhard has
|> shown that, in effect, this information is encrypted by quantum uncertainty
|> and thus cannot be used to send a faster than light signal. He also showed
|> that one can retain Lorentz invariance if one is willing to give up causality.
|> This is the approach that most physicists writing in this area have accepted.

Again, instantaneous transmission of information happens in an
underlying hidden variables theory. In the quantum theory, since it
cannot be used to send a signal, this transmission of information is
absent by definition. Also only the hidden variables theory has to
give up causality; e.g. quantum electrodynamics strictly respects
causality.

|> 
|> Since there is not a shred of evidence that the predicted nonlocal effects
|> exist, I believe, that quantum mechanics is almost certainly wrong.
|> I suspect that quantum collapse has a local Lorentz invariant structure
|> and it is this structure that constitutes the `hidden variables' that
|> determine the precise outcome of experiments. 
|> 
|> Paul Budnik

   Since quantum mechanics, quantum electrodynamics etc. give
(unambiguous) predictions verified by experiments with an incredible
accuracy (e.g.: hydrogen atom and positronium energy levels, electron
and muon magnetic moment), according to Occam's Razor we must held
these theories true until experimental evidence suggests otherwise. 
   I find "methodologically wrong" to think that, since a few
predictions of an otherwise very successful theory have not (yet) been
tested, the theory should be considered wrong.

-- 
        Massimo Campostrini, 
Istituto Nazionale di Fisica Nucleare, Sezione di Pisa,
Piazza Torricelli 2, I-56126 Pisa, Italy  ||  Phone: (+39)(50)42093
Internet: campo@sunthpi3.difi.unipi.it    ||  Fax:   (+39)(50)48277
Newsgroups: sci.physics