Minds, Machines and Multiverse: The Quest for the Quantum Computer

Computers get faster as microprocessors get smaller and denser, requiring fewer subatomic particles to toggle between zero and one. When silicon chips rely on single electrons, will computing power have hit a wall? Or will the future's computers use quantum properties to acquire undreamt-of powers? In this intriguing, fast-moving book, Brown (a longtime writer for Britain's prestigious New Scientist) asks those questions, shuttling among the physics, mathematics and information theory that would enable quantum computing, and the practical, technical work required to make it happen. He considers the class of quantum computing roadblocks that involves heat disposal, introduces us to ""complexity theory,"" something called ""decoherence"" and ""ion traps"" (the closest step yet to a quantum computer that works; research into it is currently taking place under the auspices of America's National Security Administration). Brown also profiles quantum-computer theorist David Deutsch--an engagingly eccentric Oxford physicist--as well as such famous scientists as Richard Feynman and IBM's Charles Bennett (who figured out how, ""in theory,"" ""one can compute using no energy at all""). The English-speaking world has plenty of books explaining computers, quantum theory and the attendant wacky philosophical implications, but Brown transcends these categories, showing how physics relates to computation and how their alliance affects the future of both. His enthusiastic, patient explanations of fairly difficult mathematics distinguishes his book. Illustrations. (Mar.)