The Quantum Universe_ Everything That Can Happen Does Happen - Brian Cox [0]
The Quantum Universe:
Everything that can happen does happen
ALLEN LANE
an imprint of
PENGUIN BOOKS
Contents
Acknowledgements
1. Something Strange Is Afoot
2. Being in Two Places at Once
3. What Is a Particle?
4. Everything That Can Happen Does Happen
5. Movement as an Illusion
6. The Music of the Atoms
7. The Universe in a Pin-head (and Why We Don’t Fall Through the Floor)
8. Interconnected
9. The Modern World
10. Interaction
11. Empty Space Isn’t Empty
Epilogue: the Death of Stars
Further Reading
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 encouragement, 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 fascinating. 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 natural 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. Experimenters built and operated delicate experiments to tease out the finer details of Nature. Both camps independently returned precision 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 social changes that have revolutionized our lives have arisen out of fundamental research carried out by modern-day explorers whose only motivation is to better understand the world around them. These curiosity-led voyages of discovery across all scientific disciplines have delivered increased life expectancy, intercontinental air travel, modern telecommunications, freedom from the drudgery of subsistence farming and a sweeping, inspiring and humbling vision of our place within an infinite sea of stars. But these are all in a sense spin-offs. We explore because we are curious, not because we wish to develop grand views of reality or better widgets.
Quantum theory is perhaps the prime example of the infinitely esoteric becoming the profoundly useful. Esoteric, because it describes a world in which a particle