The quantum universe : (and why anything that can happen, does)

274 Pages·2011·2.79 MB·English

by  Brian Cox

brian cox is a Professor of advance praise for B $25.00 / $28.00 CAN
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the quantum universe
Particle Physics and Royal Society IA BRIAN COX & JEFF FORSHAW
University Research Fellow at the N
“A scientifi c match made in heaven...as breezily a written accessible C Authors of the international bestseller WHY DOES E=mc2?
University of Manchester. He also
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works at the CERN laboratory account of the theory of quantum mechanics as you could wish for.” X The Quantum Universe
in Geneva. He has received many awards for his —observer & brings together the authors of

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work promoting science, including the prestigious E the international bestseller
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British Association Lord Kelvin Award and, in 2010, F Why Does E=mc2? on a brilliantly
“Breaks the rules of popular science writing...[and] admirably shies away
an OBE. He is also a popular presenter on TV and F the ambitious mission to show that
from dumbing down.... The authors’ love for their subject-matter shines O
radio. He lives in London. R everyone can understand the
through the book.” S
—the economist H quantum universe deepest questions
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jeff forshaw is Professor W of science.
of Theoretical Physics at the
University of Manchester, spe- “This offering from Brian Cox and Jeff Forshaw is a solid introduction to the
In Why Does E=mc²? professors Brian Cox and Jeff
cializing in the physics of elemen- ‘inescapable strangeness’ of the subatomic world.”
tary particles. He was awarded —nature t Forshaw took readers on a journey to the frontier
h of twenty-fi rst-century science in order to explain
the Institute of Physics Maxwell Medal in 1999 for
e and simplify the world’s most famous equation.
outstanding contributions to theoretical physics.
Now, with the same captivating clarity and infec-
He has cowritten an undergraduate textbook on q
praise for why does e=mc2?
tious enthusiasm, they’ve set out to reveal the keys
relativity and is the author of an advanced level u
to understanding one of physics’ most fascina-
monograph on particle physics. He lives in a
“[Cox and Forshaw] have blazed a clear trail into forbidding territory, from
ting yet notoriously perplexing theories: quantum
Manchester, England. n
the mathematical structure of space-time all the way to atom bombs,
mechanics.
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astrophysics, and the origin of mass.”
u Just what is quantum mechanics? How does it
—new scientist
m help us understand the world? How does it connect
with the theories of Newton and Einstein? And most

u importantly, how, despite all its apparent strange-
“I can think of no one, Stephen Hawking included, who more perfectly
n ness, can we be sure that it is a good theory?
combines authority, knowledge, passion, clarity, and powers of elucidation
i The subatomic realm has a reputation for weird-
than Brian Cox. If you really want to know how Big Science works and why v
ness, spawning theories that allow for concrete and
it matters to each of us in the smallest way then be entertained by this e
astonishing predictions about the world around us,
da capo press dazzlingly enthusiastic man.” r
—stephen fry s but also any number of profound misunderstan-
A Member of the Perseus Books Group
e
www.dacapopress.com dings. In The Quantum Universe Cox and Forshaw
cut through the confusion to provide an illumina-
Jacket design by Alex Camlin
ting—and accessible—approach to the world of
(and why anything that can happen, does)
Jacket photograph © GettyImages
quantum mechanics, revealing not only what it is
Author photographs: Brian Cox © Vincent Connare;
Jeff Forshaw courtesy of the author and how it works, but why it matters.

DaCapo Press
A Member of the Perseus Books Group
Copyright © 2011 by Brian Cox and Jeff Forshaw
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Cataloging-in-Publication data for this book is available from the Library of Congress.
First Da Capo Press edition 2012
Reprinted by arrangement with Allen Lane, an imprint of Penguin Books
ISBN 978-0-306-81964-3 (hardcover)
ISBN 978-0-306-82060-1 (e-book)
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10 9 8 7 6 5 4 3 2 1
Contents
Acknowledgements vii
1. Something Strange Is Afoot 1
2. Being in Two Places at Once 7
3. What Is a Particle? 27
4. Everything That Can Happen Does Happen 45
5. Movement as an Illusion 75
6. The Music of the Atoms 91
7. The Universe in a Pin-head (and Why We Don’t Fall
Through the Floor) 116
8. Interconnected 136
9. The Modern World 160
10. Interaction 174
11. Empty Space Isn’t Empty 196
Epilogue: the Death of Stars 215
Further Reading 243
Index 245

Acknowledgements
We’d like to thank the many colleagues and friends who helped us
‘get things right’ and provided a great deal of valuable input and
advice. Particular thanks go to Mike Birse, Gordon Connell, Mrinal
Dasgupta, David Deutsch, Nick Evans, Scott Kay, Fred Loebinger,
Dave McNamara, Peter Millington, Peter Mitchell, Douglas Ross,
Mike Seymour, Frank Swallow and Niels Walet.
We owe a great debt of gratitude to our families – to Naomi and
Isabel, and to Gia, Mo and George – for their support and encour-
agement, and for coping so well in the face of our preoccupations.
Finally, we thank our publisher and agents (Sue Rider and Diane
Banks) for their patience, encouragement and very capable support.
A special thanks is due to our editor, Will Goodlad.

1.  Something Strange Is Afoot
Quantum. The word is at once evocative, bewildering and fascinat-
ing. Depending on your point of view, it is either a testament to the
profound success of science or a symbol of the limited scope of
human intuition as we struggle with the inescapable strangeness
of the subatomic domain. To a physicist, quantum mechanics is one
of the three great pillars supporting our understanding of the nat-
ural world, the others being Einstein’s theories of Special and General
Relativity. Einstein’s theories deal with the nature of space and time
and the force of gravity. Quantum mechanics deals with everything
else, and one can argue that it doesn’t matter a jot whether it is
evocative, bewildering or fascinating; it’s simply a physical theory
that describes the way things behave. Measured by this pragmatic
yardstick, it is quite dazzling in its precision and explanatory power.
There is a test of quantum electrodynamics, the oldest and most
well understood of the modern quantum theories, which involves
measuring the way an electron behaves in the vicinity of a magnet.
Theoretical physicists worked hard for years using pens, paper and
computers to predict what the experiments should find. Experi-
menters built and operated delicate experiments to tease out the
finer details of Nature. Both camps independently returned preci-
sion results, comparable in their accuracy to measuring the distance
between Manchester and New York to within a few centimetres.
Remarkably, the number returned by the experimenters agreed
exquisitely with that computed by the theorists; measurement and
calculation were in perfect agreement.
This is impressive, but it is also esoteric, and if mapping the
miniature were the only concern of quantum theory, you might
be forgiven for wondering what all the fuss is about. Science, of
course, has no brief to be useful, but many of the technological and