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From: MJackson.Wbst@XEROX.ARPA
Newsgroups: net.physics
Subject: Re: Simple QM question
Message-ID: <1132@sri-arpa.UUCP>
Date: Wed, 23-May-84 11:13:00 EDT
Article-I.D.: sri-arpa.1132
Posted: Wed May 23 11:13:00 1984
Date-Received: Fri, 1-Jun-84 03:43:01 EDT
Lines: 16

Your experiment does not violate the Uncertainty Principle, which
governs the *simultaneous measurement* of position and momentum.  Note
that you have not simultaneously determined the position and momentum of
your particle to closer than h-bar over two (the absolute minimum, which
holds for the standard deviations of Gaussian wave packets).  Although
you know the position precisely at the moment of release, the momentum
at release is only known after detection.  There was no way to predict
the capture point, since the momentum was unknown at release.  Further,
the general behavior of subatomic particles is such that one cannot
infer from such an experiment that the particle "followed a trajectory"
in the classical sense from release to capture.

See /The Feynman Lectures on Physics/, vol. 3, early chapters, for a
clear exposition of the essentials of QM.

Mark