Quantum Computing Explained

PREFACE

“In the twenty-first” century it is reasonable to expect that some of the most important developments in science and engineering will come about through interdisciplinary research. Already in the making is surely one of the most interesting and exciting development we are sure to see for a long time, quantum computation. A merger of computer science and physics, quantum computation came into being from two lines of thought. The first was the recognition that information is physical, which is an observation that simply states the obvious fact that information can’t exist or be processed without a physical medium.

At the present time quantum computers are mostly theoretical constructs. However, it has been proved that in at least some cases quantum computation is much faster in principle than any done by classical computer. The most famous algorithm developed is Shor’s factoring algorithm, which shows that a quantum computer, if one could be constructed, could quickly crack the codes currently used to secure the world’s data. Quantum information processing systems can also do remarkable things not possible otherwise, such as teleporting the state of a particle from one place to another and providing unbreakable cryptography systems.

Our treatment is not rigorous nor is it complete for the following reason: this book is aimed primarily at two audiences, the first group being undergraduate physics, math, and computer science majors. In most cases these undergraduate students ...