Decoherence And The Appearance Of A Classical World In Quantum Theory

A unique description of the phenomena that arise from the interaction between quantum systems and their environment. Because of the novel character of the approach discussed, the book addresses scientists from all fields of physics and related disciplines as well as students of physics.

Decoherence, a concept known only to few physicists when the first edition appeared in 1996, has since become firmly established experimentally and understood theoretically, as well as widely reported in the literature. The major consequences of decoherence are the emergence of "classicality" in general, superselection rules, the border line between microscopic and macroscopic behavior in molecules and field theory, the emergence of classical spacetime, and the appearance of quantum jumps. The most important new developments in this rapidly evolving field are included in the second edition of this book, which has become a standard reference on the subject. All chapters have been thoroughly revised and updated. New fields of application now addressed span chaos theory, quantum information, neuroscience, primordial fluctuations in cosmology, black holes and string theory, experimental tests, and interpretational issues. While the major part of the book is concerned with environmental decoherence derived from a universal Schrödinger equation, later chapters address related or competing methods, such as consistent histories, open system dynamics, algebraic approaches, and collapse models.

This fascinating book explores how a seemingly classical macroscopic world can evolve from a microscopic world based on quantum systems. While sometimes contradictory, the views expressed here reflect the lively nature of the debate within science about the nature of reality and the implications of quantum theory.

This detailed, accessible introduction to the field of quantum decoherence reviews the basics and then explains the essential consequences of the phenomenon for our understanding of the world. The discussion includes, among other things: How the classical world of our experience can emerge from quantum mechanics; the implications of decoherence for various interpretations of quantum mechanics; recent experiments confirming the puzzling consequences of the quantum superposition principle and making decoherence processes directly observable.

With contributions by leading quantum physicists, philosophers and historians, this comprehensive A-to-Z of quantum physics provides a lucid understanding of key concepts of quantum theory and experiment. It covers technical and interpretational aspects alike, and includes both traditional and new concepts, making it an indispensable resource for concise, up-to-date information about the many facets of quantum physics.

Over the course of the past decade, decoherence has become a ubiquitous scienti?c term popular in all kinds of research, from fundamental theories of quantum physics to applications in nanoengineering. Decoherence has been hailed as the solution to long-standing foundational problems dating back to the beginnings of quantum mechanics. It has been cursed as the key obstacle to next-generation technologies, such as quantum computers (another se- ingly omnipresent ?eld of research). And while decoherence has been directly observed in various experiments, its scope and meaning have often been m- understood and misrepresented. Decoherence makes a fantastic subject of research, as it touches upon many di?erent facets of physics, from phi- sophically inclined questions of interpretation all the way to down-to-earth problems in experimental settings and engineering applications. This book will introduce the reader, in an accessible and self-contained manner, to these various fascinating aspects of decoherence. It will focus in particularontherelationofdecoherencetotheso-calledquantum-to-classical transition, i. e. , the question of how decoherence may explain the emergence of the classical appearance of the macroscopic world around us from the underlying quantum substrate. Thescopeofthisbookisrelativelybroadinordertofamiliarizethereader withthemanyfacetsofdecoherence,inboththetheoreticalandexperimental domains. Throughout the book, I have sought to maintain a healthy balance betweentheconceptualideasassociatedwiththedecoherenceprogramonthe one hand and the formal and mathematical details on the other hand. This book will establish a proper understanding of decoherence as a pure quantum phenomenon and will emphasize the importance of the correct interpretation of theconsequences and achievements of decoherence.

This volume is devoted to Quantum Decoherence with lectures from the Séminaire Poincaré, held in November 2005 at the Institute Henri Poincaré Paris. The goal of this seminar is to provide up-to-date information about general topics of great interest in physics. Both the theoretical and experimental results are covered, with some historical background. Particular care is devoted to the pedagogical nature of the presentation.

“Anyone who is not shocked by quantum theory has not understood it.” Since Niels Bohr said this many years ago, quantum mechanics has only been getting more shocking. We now realize that it’s not really telling us that “weird” things happen out of sight, on the tiniest level, in the atomic world: rather, everything is quantum. But if quantum mechanics is correct, what seems obvious and right in our everyday world is built on foundations that don’t seem obvious or right at all—or even possible. An exhilarating tour of the contemporary quantum landscape, Beyond Weird is a book about what quantum physics really means—and what it doesn’t. Science writer Philip Ball offers an up-to-date, accessible account of the quest to come to grips with the most fundamental theory of physical reality, and to explain how its counterintuitive principles underpin the world we experience. Over the past decade it has become clear that quantum physics is less a theory about particles and waves, uncertainty and fuzziness, than a theory about information and knowledge—about what can be known, and how we can know it. Discoveries and experiments over the past few decades have called into question the meanings and limits of space and time, cause and effect, and, ultimately, of knowledge itself. The quantum world Ball shows us isn’t a different world. It is our world, and if anything deserves to be called “weird,” it’s us.