The Quantum World Unveiled by Electron Waves

172 Pages·1996·91.928 MB·English

by  Akira Tonomura

The Quantum
World Unveiled by
Electron Waves
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The Quantum
World Unveiled by
Electron Waves
Akira Tonomura
World Scientific
SSiinnqgaappoorree •• NNeeww JJeerrsseeyy •• LL ondon • Hong Kong
Published by
World Scientific Publishing Co. Pte. Ltd.
P O Box 128, Farrer Road, Singapore 912805
USA office: Suite IB, 1060 Main Street, River Edge, NJ 07661
UK office: 57 Shelton Street, Covent Garden, London WC2H 9HE
British Library Cataloguing-in-Publication Data
A catalogue record for this book is available from the British Library.
First published 1998
Reprinted 2000
THE QUANTUM WORLD UNVEILED BY ELECTRON WAVES
Copyright © 1998 by World Scientific Publishing Co. Pte. Ltd.
All rights reserved. This book or parts thereof, may not be reproduced in any form or by any means, electronic or
mechanical, including photocopying, recording or any information storage and retrieval system now known or to
be invented, without written permission from the Publisher.
For photocopying of material in this volume, please pay a copying fee through the Copyright Clearance Center,
Inc., 222 Rosewood Drive, Danvers, MA 01923, USA. In this case permission to photocopy is not required from
the publisher.
ISBN 981-02-2510-5
Printed in Singapore.
Preface
This book is an interesting personal account in non-technical terms of the research
experience in basic sciences by one of the world's greatest experts on electron waves.
It covers many facets of his beautiful works in the last thirty years.
Electrons, nuclei and photons are the particles that are the main subjects of
study of twentieth century physics. Based on such studies there was remarkable
success in the manipulation of the motions and intereactions of these particles,
giving rise in turn to the new technologies of the twentieth century. This success is
obviously going to be continued into the next century, with profound implications
for the economies of the industrialized world.
Matter is made of electrons and nuclei. Since nuclei are heavy and tightly bound,
and cannot be easily broken apart, properties of matter are usually determined by
the motions of electrons. This explains, a priori, why the study of the properties
of the motions of electrons is so important. Dr. Tonomura's success began with his
ability to produce coherent motion of electrons. This success led him to previously
unattainable precision in many beautiful experiments.
The personal touch adds flavor to the book. Although the author often has to
venture into technical details in describing some developments, it is worthwhile for
the reader to wade through such passages of heavy reading since the author does
succeed in describing the great intellectual and practical excitement involved in such
developments, bringing to life the feelings of a scientist in the frontiers of research.
Chen Ning Yang
v
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Prologue
I wrote this monograph to excite people's curiosity about the strange behavior
of electrons seen in the microscopic world, behavior quite different from those of
common objects we see in our daily life. The story begins with my Friday Evening
Discourse at the Royal Institution in Great Britain on November 4, 1994. This event
gave me my first chance to talk to laymen while using demonstration experiments,
and it made me think about "science in the society" and finally made me take
up my pen. I would not like to simply describe a dry collection of knowledge but
instead to tell you of the enthusiasm, joy, and difficulty of my own research. Among
the fields of science treated in this book are quantum mechanics, superconductivity,
electron microscopy, holography, magnetism, and unified theories. These are the
fields I explored using electron waves.
"Why did I write such a book?" Because I want young people to enter the fields
of physics where there are still many interesting problems to be solved. We need
young people who think logically and deeply. No, such abilities may be cultivated
later on. However, I believe those who are most suitable are moved by beauty and
think that it is worthwhile even to spend their whole lives to see the beauty of
Nature.
In any case, things become difficult when you want to open a new way. Although
you might feel uneasy about whether you can do such a thing alone, you might
instead become courageous and awaken your adventurous spirit.
When you throw yourself into your curiosity and dare to dream, there will often
be times you are not successful. Even in that case, you should never get discouraged
but forget the failures soon, thinking that this is due to your shallow considerations.
But once in a while when you succeed and peep into the beauty of Nature, you will
be indescribably delighted. I wrote this book expecting lots of readers to think, "If
there is such a way, I want to step forward on that way!".
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Contents
Preface v
Prologue vii
Chapter 1 Magnetic Lines of Force 1
Chapter 2 What Are Waves? 6
Chapter 3 Interfering Electrons 14
Chapter 4 Electron Holography 24
Chapter 5 Coherent Electron Beams Developed! 36
Chapter 6 Wave-Particle Duality 45
Chapter 7 Interference Electron Microscopy 61
Chapter 8 Magnetic Lines of Force in the Microscopic World 70
Chapter 9 The Aharonov-Bohm Effect 83
Chapter 10 Vector Potentials, Real or Not? 90
Chapter 11 Quantum World in Superconductors 114
Epilogue 157
ix