 |
 |
 |
 |
 |
 |
|
|||
 |
 |
 |
|||||||
| Copyright © 2012. National Academy of Sciences. All rights reserved. Terms of Use and Privacy Statement |
Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter.
Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.
OCR for page R1
Schrödinger’s Rabbits: The Many Worlds of Quantum
SCHRÖDINGER’S RABBITS
OCR for page R2
Schrödinger’s Rabbits: The Many Worlds of Quantum
This page intentionally left blank.
OCR for page R3
Schrödinger’s Rabbits: The Many Worlds of Quantum
SCHRÖDINGER’S RABBITS
the many worlds of quantum
Colin Bruce
Joseph Henry Press
Washington, DC
OCR for page R4
Schrödinger’s Rabbits: The Many Worlds of Quantum
Joseph Henry Press
500 Fifth Street, N.W. Washington, D.C. 20001
The Joseph Henry Press, an imprint of the National Academies Press, was created with the goal of making books on science, technology, and health more widely available to professionals and the public. Joseph Henry was one of the founders of the National Academy of Sciences and a leader in early American science.
Library of Congress Cataloging-in-Publication Data
Bruce, Colin.
Schrödinger’s rabbits : the many worlds of quantum / Colin Bruce.
p. cm.
ISBN 0-309-09051-2 (case)
1. Quantum theory—Popular works. I. Title.
QC174.12.B78 2004
530.12—dc22
2004021021
Any opinions, findings, conclusions, or recommendations expressed in this volume are those of the author and do not necessarily reflect the views of the National Academy of Sciences or its affiliated institutions.
Cover design by Michele de la Menardiere.
Copyright 2004 by Colin Bruce. All rights reserved.
Hand-drawn illustrations by Laura Dawes from sketches by Colin Bruce.
Printed in the United States of America
OCR for page R5
Schrödinger’s Rabbits: The Many Worlds of Quantum
Dedicated to
Paul Dirac physicist extraordinary who believed we must seek visualizable processes
and
Jim Cushing philosopher of science who believed we must find local stories
OCR for page R6
Schrödinger’s Rabbits: The Many Worlds of Quantum
This page intentionally left blank.
OCR for page R7
Schrödinger’s Rabbits: The Many Worlds of Quantum
PREFACE
Does the weirdness of quantum indicate that there is a deep problem with the theory? Some of the greatest minds in physics, including Einstein, have felt that it does. Others prefer to believe that any conceptual difficulties can be ignored or finessed away. I would put the choice differently. The flip side of a problem is an opportunity, and the problems with the old interpretations of quantum present us with valuable opportunities.
First, there is the hope of finding ways to think more clearly about the subject. I have several times seen highly respected scientists—physicists whose ability to work with the math of quantum mechanics is certainly better than my own—make appalling freshman howlers in describing what the result of an experiment would be, because their qualitative thinking about such matters as quantum collapse was as fuzzy as everyone else’s. Better conceptual tools are badly needed—and now they are becoming available.
Second, there is the possibility that a clearer view of quantum will cause us to see the universe in a fundamentally different way, with implications both practical and philosophical. Then, as has happened so many times in physics, the resolution of a seemingly arcane problem will open our eyes to great new wonders. To ignore such an opportunity would be sheer cowardice.
The past few years have seen a sudden explosion of light in the
OCR for page R8
Schrödinger’s Rabbits: The Many Worlds of Quantum
murkier corners of quantum. The old stories, involving such quaint characters as dead-alive cats and conscious observers with the power to “collapse” the whole universe, or even split it in two, are passé. There are new stories to choose from, one of them particularly promising. It restores us to a classical universe where things behave predictably rather than randomly and where interactions between things are local rather than long range. But it comes at a price. We must accept that the universe we inhabit is much vaster than we thought, in an unexpected way.
Although the many-worlds view was invented in the United States, it is in Europe, and especially in Oxford, that it has developed to maturity. That is my good luck, for I have had the privilege of seeing the process at first hand. Here I describe the remarkable new picture that has recently emerged, which I dub the Oxford Interpretation.
My warmest thanks go to my editor Jeff Robbins at Joseph Henry Press for his vision and determination in ensuring that this book came to be. Also to many physicists and philosophers at Oxford and elsewhere for valuable advice and discussion, including in particular Harvey Brown, David Deutsch, Roger Penrose, Simon Saunders, David Wallace and Anton Zeilinger. Special thanks to Lev Vaidman, Jacob Foster, and Heather Bradshaw, who read the manuscript at an advanced stage and made many useful comments. Responsibility for any mistakes that remain, and any controversial opinions expressed herein, is of course entirely my own.
Colin Bruce
Oxford, 2004
OCR for page R9
Schrödinger’s Rabbits: The Many Worlds of Quantum
CONTENTS
1
A Magical Universe
1
2
Clinging to the Classical
13
3
Collapse by Inference
27
4
A Horror Story Writ Large
40
5
The Old Testament
57
6
Let’s All Move into Hilbert Space
74
7
Pick Your Own Universe
92
8
A Desirable Locality
106
9
Introducing Many-Worlds
126
10
Harnessing Many-Worlds 1: Impossible Measurements
140
11
Harnessing Many-Worlds 2: Impossible Computers
155
12
Many-Worlds Heroes and Dragons
169
13
The Terror of Many-Worlds
185
14
The Classical Warrior: Roger Penrose
198
15
The New Age Warrior: Anton Zeilinger
211
16
Proving and Improving Many-Worlds
228
Appendix
251
Notes
253
Index
261
OCR for page R10
Schrödinger’s Rabbits: The Many Worlds of Quantum
This page intentionally left blank.
