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From: ethan@utastro.UUCP (Ethan Vishniac)
Newsgroups: net.physics
Subject: Re: Bell's Inequality
Message-ID: <90@utastro.UUCP>
Date: Tue, 14-May-85 12:33:31 EDT
Article-I.D.: utastro.90
Posted: Tue May 14 12:33:31 1985
Date-Received: Thu, 16-May-85 06:34:48 EDT
References: <590@astrovax.UUCP>
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Organization: U. Texas, Astronomy, Austin, TX
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> 
> My own opinion is that QM is at best an incomplete theory since it must rely
> on classical (non-quantum) descriptions of the act of measurement to obtain
> "the collapse of the wave function".  If one sticks entirely to QM wave
> functions, there is no collapse to particular eigen states.  
> 
> Ed Turner
> astrovax!elt

This is the crucial point.  Suggestions I have heard to solve this problem
range from
  1) Quantum gravity will lead to an understanding of wave function collapse
once the gravitational energy of the wave function is included. [This argument
is due to Penrose.]

  to

 2) The spread of the wave function describes the branching of the universe.
This is the "many-worlds" interpretation of QM due to Evrett and Wheeler
(with some substantial contribution by Bryce Dewitt).

Neither strikes me as entirely satisfactory.  Quantum gravity may solve 
everything, but until we know what it is (1) is no more than a pious hope.

(2) is an extravagant solution in the sense that we resolve our difficulties
by creating an infinity of universes branching out from every quantum 
interaction.

"Don't argue with a fool.      Ethan Vishniac
 Borrow his money."            {charm,ut-sally,ut-ngp,noao}!utastro!ethan
                               Department of Astronomy
                               University of Texas