Einsteins Struggles With Quantum Theory: A Reappraisal

Einstein’s Struggles with Quantum Theory Einstein’s Struggles with Quantum Theory A Reappraisal Dipankar Home Bose Institute, Kolkata and Andrew Whitaker Queen’s University Belfast Dipankar Home Bose Institute Kolkata Andrew Whitaker Queen’s University Belfast Library of Congress Control Number: 2006931196 ISBN-13: 978-0-387-71519-3 e-ISBN-13: 978-0-387-71520-9 Printed on acid-free paper. © 2007 Springer Science+Business Media, LLC All rights reserved. This work may not be translated or copied in whole or in part without the written permission of the publisher (Springer Science+Business Media, LLC, 233 Spring Street, New York, NY 10013, USA), except for brief excerpts in connection with reviews or scholarly analysis. Use in connection with any form of information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed is forbidden. The use in this publication of trade names, trademarks, service marks, and similar terms, even if they are not identified as such, is not to be taken as an expression of opinion as to whether or not they are subject to proprietary rights. 9 8 7 6 5 4 3 2 1 springer.com The authors respectfully dedicate this book to the memory of David Bohm and John Stewart Bell whose pioneering work did so much to demonstrate the importance of Einstein’s views and arguments on quantum theory. Contents Foreword by Sir Roger Penrose xiii Preface xvii Part A Setting the Scene 1 1. The Philosophical Background: Einstein and Mach Introduction Positivism and Ernst Mach Mach’s Critique of Newton Einstein and Mach—Part 1 Einstein and Mach—Part 2 Einstein and Mach—the Denouement References 3 3 4 6 8 12 16 17 2. Einstein and Quantum Theory: The Early Years Einstein and the Development of Quantum Theory The Photon and Specific Heats Spontaneous and Stimulated Emission; Probability and Statistics The Path to the New Quantum Theory The New Quantum Theory: Bohr and Heisenberg The New Quantum Theory: Einstein’s Contributions References 21 21 23 3. Quantum Mechanics and Its Fundamental Issues Introduction Some Preliminaries The Uncertainty Principle ‘Time-Energy Uncertainty Principle’ Pure and Mixed States Statistical Properties of Pure States Statistical Properties of Mixed States Observable Distinction Between a Pure and a Mixed State 39 39 40 44 45 46 47 48 48 26 29 30 32 36 vii viii Contents Classical Realism or Macrorealism Quantum Realism The Quantum Measurement Problem The Classical Limit Problem of Quantum Mechanics The Limit Problem: Wave and Ray Optics The Limit Problem: Special Relativity and Newtonian Mechanics The Classical Limit Problem in Standard Quantum Mechanics Wave-Particle Duality References 50 50 51 53 54 4. The Standard Interpretation of Quantum Mechanics Introduction The Bohr–Heisenberg Version The Ensemble Interpretation Single System vis-à-vis Ensemble Interpretation The Bohr–Heisenberg ‘Solution’ to the Quantum Measurement Problem Position-Momentum Complementarity Wave-Particle Complementarity Bohr and the ‘Disturbance Interpretation’ von Neumann and the Projection Postulate von Neumann’s Impossibility ‘Proof’ References 59 59