Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 8/28/84; site lll-crg.ARPA Path: utzoo!watmath!clyde!burl!ulysses!mhuxr!mhuxt!houxm!mtuxo!mtunh!mtung!mtunf!ariel!vax135!cornell!uw-beaver!tektronix!hplabs!qantel!dual!lll-crg!brooks From: brooks@lll-crg.ARPA (Eugene D. Brooks III) Newsgroups: net.physics Subject: Re: Re: Re: Faster than Light Message-ID: <686@lll-crg.ARPA> Date: Sun, 7-Jul-85 17:55:19 EDT Article-I.D.: lll-crg.686 Posted: Sun Jul 7 17:55:19 1985 Date-Received: Fri, 12-Jul-85 05:02:47 EDT References: <353@sri-arpa.ARPA> <681@lll-crg.ARPA> <11387@brl-tgr.ARPA> Organization: Lawrence Livermore Labs, CRG group Lines: 43 > > is not however real physical entity like for instance an electric field. > > (followed by a discussion about how the wave function isn't real) > > Everything you say about the QM wave function could also be said about > the electric field. What makes the electric field any more real than > the QM wave function? The wave function and the electric field have one fundamental difference. The electric field is observable in a single experiment. The wave function is not. When an electric field collapses the stored energy density has to go somewhere and there are measureable physical consequences. The electric field certainly did have its beginnings as a computational device. And I think that this is the root of your your comment. I in fact won't argue with anyone about whether or not it is real. It is likely that you can have it both ways. The wave function is a different sort of animal. It is used to describe the probabilistic results of a large number of identical experiments. It can be measured only by repeating the identical experiment. When it "collapses" there are no measureable consequences of the "motion". The "collapase" is only there to explain the fact that when the particle is detected at one place it is not going to be detected elsewhere. The wave function (squared) gives the probability of one of several choices. It is inherently not measureable in the context of a single experiment. Reality, like beauty, is in the eye of the beholder. I will not further harass anyone who wants to think of the wavefunction as a real thing that is distributed in space and moving around. When using the Schrodinger picture (See QM by Messiah for discussion on this) I tend to think of the wave function as a 'real' field that is distributed over space and is moving around. Consider, however, the Heisenberg picture where the wavefunction is a constant vector and its the operators that move around. You can of course have if anywhere in between. A case in point is the Interaction picture. When someone wants want to worry about the wavefunction's "instantaneous collapse" as being in potential violation of relativity or unasthetic he/she is thinking that the wavefunction is a bit more real than it really is. This is something that is not in the eye of the beholder and can clearly labeled as a misinterpretation of the facts.