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From: gjphw@iham1.UUCP (wyant)
Newsgroups: net.physics
Subject: Re: Quantum Mechanics
Message-ID: <413@iham1.UUCP>
Date: Sat, 13-Jul-85 11:28:44 EDT
Article-I.D.: iham1.413
Posted: Sat Jul 13 11:28:44 1985
Date-Received: Sun, 14-Jul-85 08:42:46 EDT
References: <365@sri-arpa.ARPA>
Organization: AT&T Bell Laboratories
Lines: 42

> 

    This is a brief comment on Peter Mikes' submission concerning the adequacy
 of quantum mechanics.  While I am not prepared to address all of the issues
 Peter raised in his article, there are a few points that have been mentioned
 previously in this news group.

    First, A. Einstein's et al interpretation of quantum mechanics is in
 jeopardy.  The Aspect experiment, a test of Bell's Inequality, appears to be
 an unequivocal demonstration that hidden variables and/or Einstein causality
 cannot provide a proper explanation of phenomena in the quantum mechanical
 realm.  The significance of Bell's Inequality has been discussed in this news
 group.  I refer those interested to a very readable article by J. Rosen in a
 recent PHYSICS TODAY that treats the interpretation and evaluation of the
 Aspect experiment.

    Second, a recent article in the AMERICAN JOURNAL OF PHYSICS (a journal of
 physics demonstrations, history, and interpretations intended for college
 level physics instructors) discussed the history and meaning of Bell's
 Inequality, Einstein causality, and the completeness of quantum mechanics.
 The author suggested that in addition to the two standard interpretations for
 the measurement process in QM (wavefunction collapse and multiple worlds), a
 third interpretation originally proposed by Max Born also deserves
 consideration.  I cannot claim to understand the "potentia" interpretation at
 this time, but perhaps some other interested party could explain this to us.

    Finally, I have difficulty understanding Peter's perspective on
 completeness.  Two possibilities occur to me.  One is that I can ask all sorts
 of questions, but if they cannot be answered by QM, then QM as it is currently
 constructed is incomplete.  Another possibility is that no matter what I may
 want, if QM cannot answer it then there is no answer.  This second operational
 approach, used quite successfully in the Special Theory, would say that QM is
 complete.  Our interpretations are merely vain attempts to convert a
 mathematical formalism into common language.

    Personally, I am not very conversant with the measurement problem in QM,
 having merely been content to turn in my homework sets on time.  The
 sophisticated discussion will have to come from elsewhere.

                             Patrick Wyant
                             AT&T Bell Laboratories (Naperville, IL)
                             *!iham1!gjphw