Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!watmath!clyde!burl!ulysses!mhuxr!mhuxt!houxm!vax135!cornell!uw-beaver!tektronix!hplabs!sri-unix!mikes@AMES-NAS.ARPA From: mikes@AMES-NAS.ARPA Newsgroups: net.physics Subject: none Message-ID: <718@sri-arpa.ARPA> Date: Thu, 31-Oct-85 17:07:06 EST Article-I.D.: sri-arpa.718 Posted: Thu Oct 31 17:07:06 1985 Date-Received: Mon, 4-Nov-85 02:14:44 EST Lines: 60 From: mikes@AMES-NAS.ARPA (Peter Mikes) re: Quantum Reality I want to comment on the book: Quantum Reality by Nick Herbert (Doubleday 85) [ ISBN 0-385-18704-1 $19...] which covers in detail some topics touched upon in past discussions of this group - such as EPR, Bells theorem, collapse of wave function and in general interpretation of the QM and its Measurement Problem... Herbert describes three interpretations of the measurement in QM (p146) a) Copenhagen int - There is no 'deep reality'. This includes original Bohrs ' only the clics of the Geiger counters are 'real'..' and Wheelers "Austin interpretation" of the 'observer created reality' related to 'Delayed Choice exp' (pp164-166). b) All-Quantum int - based on Von Neumann's Grundlagen.. offers a unified view, in which the QM is 'the deep reality' underlying Classical phenomena just as Relativity offers deeper explanation for e.g. Maxwell eq. and of Newtons laws.. c) Neorealist int - which inherited all former 'hidden parameters theories' and Stochastic Mechanics attempts starting with Fenyes and includes Bohm's Quantum potential as a Pilot Wave. This is the dissident view, which most people seem to believe was killed by the experiment and Bells theorem. I want - first of all - to recommend the book. If I recall correctly, I am so far only one who confessed on net.physics to the heresy of neorealism and so by this 'endorsement' I want to say that the 'minority view' is fairly presentedin the book (while apparently not professed by the author). A short biased comment on the merit of the three interpretations: All three appear to have problems: c) requires FTL interactions which are unobserved. I want to stress: so far not observed directly. Compare that with ortho- dox views a) and b) which are inherently non-local and so include "actions" which are instant distant and un-observable. They may appear less offensive as they seem to be more ghostlike, less real.. - a collapsing psi? So what? What is psi anyway.. Herbert treats well the issue of 'perturbation by measurement' as underlying cause of quantum phenomena. This is a halftruth and cliche propagated by most if not all textbooks. One of the results EPR achieved was to discredit that. If you are still captive of that essentialy classic paradigm read page 110: " Heisenberg principle follows from .. and has nothing to do with the 'unavoidable disturbance of the system by measurement'." Also valuable is discussion on pp150-152: Is it measurement (by conscious observer?) or is it just an natural process (of amplification?) which is responsible for 'collapses' and how to 'revive a dead Shrodinger cat' by performing a conjugate measurement. (This is the 'irreversibility connection' of the QM Measurement problem upon which we have touched lightly in the past). The book is written for a layman, assumes nothing, and so by necessity contains (still another) non-mathematical exposure of QM. There are occasional weaknesses - e.g. on page 35 statement : " Planck's assumption (of E=n*h*f) was not justified by any physical reasoning.." is most unfair. However, the book goes further then other exposures in explaining Bell theorem and EPR arguments (BEPRA?) - which as >I hope we all know< are the crucible from which the Phoenix of the new theory will arise... and so provides an valuable contribution. Dont miss it.