Many-worlds Interpretation Of Quantum Mechanics (princeton Series In Physics)

The Many-Worlds Interpretation of Quantum Mechanics , Princeton Series in Physics edited by Arthur S. Wightman and John J. Hopfield Quantum Mechanics for Hamiltonians Defined as Quadratic Forms by Barry Simon Lectures on Current Algebra and Its Applications by Sam B. Treiman, Roman Jackiw, and David J. Gross Physical Cosmology by P. 1. E. Peebles The Many-Worlds Interpretation of Quantum Mechanics edited by B. S. DeWitt and N . Graham A Fundamental Exposition by HUGH EVERETT, 111, with Papers by J. A. WHEELER, B. S. DEWITT, L. N. COOPER and D. VAN VECHTEN, and N. GRAHAM Edited by BRYCE S. DEWITT and NEILL GRAHAM Princeton Series in Physics Princeton University Press Princeton, New Jersey, 1973 Copyright @ 1973, by Princeton University Press All Rights Reserved PREFACE LC Card: 72-12116 ISBN: 0-691-08126-3 (hard cover edition) ISBN : 0-69 1-8813 1-X (paperback edition) In 1957, in h i s Princeton doctoral d i s s e r t a t i o n , Hugh Everett, 111, proposed a new interpretation of quantum mechanics that d e n i e s the exist- Library of Congress Cataloguing in Publication data will be found on the last printed page of this book. The following papers have been included in this volume with the permission of the copyright owners: 'Relative State' Formulation of Quantum Mechanics" by Hugh Everett 111, and "Assessment of Everett's 'Relative State' Formulation of Quantum Theory," by John A. Wheeler, copyright July 1957 by The Review o f Modern Physics; "Quantum Mechanics and Reality," by Bryce S. DeWitt, copyright September 1970 by Physics Today; "The Many-Universes Interpretation of Quantum Mechanics," by Bryce S. DeWitt, in Proceedings o f the international School of Physics "Enrico Fermi" Course IL: Foundations of Quantum Mechanics, copyright 1972 by Academic Press; "On the Interpretation of Measurement within the Quantum Theory," by Leon N. Cooper and Deborah van Vechten, copyright December 1969 by Ameiican Journal of Physics. The epigraph is taken from "The Garden of Forking Paths," from Ficciones by Jorge Luis Borges, copyright 1962 by Grove Press, Inc.; translated from the Spanish, copyright 1956 by Emece Editores, SA, Buenos Aires. " e n c e of a s e p a r a t e c l a s s i c a l realm and a s s e r t s t h a t i t m a k e s s e n s e t o t a l k about a s t a t e vector for t h e whole universe. T h i s s t a t e vector never col- I l a p s e s , and h e n c e reality a s a whole is rigorously deterministic. T h i s reality, which is described jointly by t h e dynamical variables and t h e s t a t e vector, is not t h e reality w e customarily think of, but is a reality composed of many worlds. By virtue of t h e temporal development of t h e dynamical v a r i a b l e s t h e s t a t e vector decomposes naturally into orthogonal vectors, reflecting a continual s p l i t t i n g of t h e universe into a multitude of mutually unobservable but equally real worlds, i n e a c h of which every good measurement h a s y i e l d e d a d e f i n i t e result and in most of which the familiar s t a t i s t i c a l quantum l a w s hold. In addition t o h i s short t h e s i s Everett wrote a much larger exposition of h i s i d e a s , which w a s never published. T h e p r e s e n t volume c o n t a i n s both of t h e s e works, together with a handful of papers by others on t h e s a m e theme. Looked a t in o n e way, Everett's interpretation c a l l s for a return t o n a i v e realism and t h e old fashioned i d e a that there c a n b e a Printed in the United States of America by Princeton University Press direct correspondence between formalism and reality. B e c a u s e p h y s i c i s t s h a v e become more s o p h i s t i c a t e d than t h i s , and a b o v e a l l b e c a u s e t h e implications of