Quantum

by Manjit Kumar

If some aspects of physics are astounding, quantum mechanics is practically magical. There's been a great deal of debate amongst physicists about what it actually means. Quantum tells the story of this debate, taking in some of the most profound discoveries in this field during the 20th century, and how it affected the scientists at the forefront of the drive to understand its implications.

This book is a history, and it balances descriptions of the scientific concepts with details of the personalities and lives of the people involved. The early chapters on Max Planck and his investigations into blackbody radiation are easy to follow. This is partly because the level of scientific knowledge wasn't yet at the stage of becoming baffling to all involved, and also because the account is spiced up with the personal struggles and petty politics he faced before he became a household name. However the simplicity doesn't last.

Quantum physics seems like a relatively new concept, but what's remarkable is how early it was discovered and argued over. Theoretical physicists seem to have been in a stage of crisis ever since. The book follows the lives and discoveries of scientists such as Albert Einstein, Ernest Rutherford, Niels Bohr, Werner Heisenberg, Wolfgang Pauli, Louis de Broglie, Erwin Schrödinger, and others, most of whom won Nobel prizes for their efforts. The lumpy, discontinuous microscopic world, Einstein's theories about relativity and the way it affects time, quantum entanglement, and the impossibility of measuring an object's precise position as well as its momentum: these ideas all seem counter-intuitive, or even crazy. So it's perhaps unsurprising that each breakthrough was met with a period of doubt before it was accepted as part of the scientific orthodoxy.

The search for truth hasn't been a steady process, thanks to the interruptions of two world wars and the occasions when groundbreaking research has gone ignored or misunderstood for years. This is a fascinating mix of science and the personal lives of the scientists, juiced up by intellectual spats and the colourful personal lives of characters like Einstein and Schrödinger. So Quantum is certainly not a dry book, although it does tackle some difficult concepts and certain chapters are demanding. However it's makes a clear explanation of quantum mechanics, to the extent that it can be understood given that it remains a source of confusion even amongst professional scientists. There are a few equations, but not so many that a non-specialist should feel daunted by them.

The heart of this book is the great schism between Einstein and Bohr over the objective reality of the unobserved world. Does it even exist outside of our ability to perceive it? It's a debate that extends to the limits of science, where faith necessarily takes the place of reason, and even the smartest minds are reduced to relying on instinct rather than provable facts. Manjit Kumar captures the passion that went into these arguments whilst he explains what they were about. He succeeds in making some very complex subject matter accessible without oversimplifying it. This is a well-researched book that's as informative about 20th century history and famous scientists as it is about quantum physics. It's a real eye-opener into the invisible sub-atomic world.