Decoherence and the Quantum-to-Classical Transition (The Frontiers Collection)

Considering the claims made by experimentalists on the creation of macroscopic quantum systems, and the creation of quantum computers and quantum networks, interested (and possibly skeptical) individuals with a background in quantum physics will appreciate a focused account that will outline some of the major impediments to these claims.The phenomenon of decoherence can act as impediment to the creation of macroscopic quantum systems as well as inhibiting the operation of true quantum computers and quantum networks. This excellent book gives a detailed overview of the subject of decoherence, both from a theoretical and experimental point of view, and will definitely serve readers who want to understand what inhibits the realization of certain technologies based on quantum physics, as well as readers who desire an in-depth understand of decoherence for its own sake.The author gives an outline of the subject that is quantitative and so he is not shy about using the appropriate mathematical formalism whenever it is needed. However, he does not hesitate to motivate the subject using the typical hand-waving and demonstrative strategies that are deployed effectively by good instructors of physics. Readers therefore are expected to understand quantum physics at the advanced undergraduate or beginning graduate level. Philosophers of science or epistemologists may also find this book of interest, especially the discussions on the emergence of classicality of physical systems and the last two chapters.Some of the interesting topics and discussions in the book include:- Emphasis on decoherence as being a purely quantum-mechanical phenomenon that does not have a classical analog. Along these same lines, the role of entanglement as enforcing the observed classical behavior of physical systems.- The discussion on the spreading of wave packets (discussed early on in many textbooks in quantum physics), and its diminution by interactions with the environment.- The importance of distinguishing quantum (i.e. coherent) superposition from a mere classical ensemble or mixture of components. The author’s proof that superpositions are not classical ensembles of component states is non-constructive (based on deriving a contradiction). This may be distasteful to the philosopher-reader who insists on strict constructive proofs for all assertions.- The explanation that decoherence does not destroy superposition but extends it to include the environment.- The assertion on the need for a quantitative measure of the degree to which a state is entangled. This is widely discussed in the literature on entanglement.- The need for understanding decoherence as arising from the distinguishability of the states of one system that are correlated with the states of another system (the environment). Interestingly, the author describes quantum coherence as being a shared property of the system/environment state, with decoherence inhibiting the observation of this coherence at the system level.- The author’s clarification that the lack of interference terms in the density matrix does not imply that the system lacks quantum properties, contrary to what is claimed in some of the literature on the subject.- The assertion that the interpretation of the trace rule relies fundamentally on the Born rule.- The author’s clarification that mixed state density matrices represent classical ensembles, familiar to the coarse-graining operations that go on in classical statistical mechanics, and the corresponding probabilities are not to be viewed in any way as fundamental. Mixed states are to be differentiated from superpositions of pure states, and pure-state density matrices are to be differentiated from mixed-state density matrices. Only when one performs an ensemble average is it meaningful to speak of ensembles of physical systems being described by single-system mixed-state density matrices. Some of the literature on this subject is confusing.- The remarkably interesting discussion of the connection between the double-slit experiment with entanglement. This connection is not typically discussed in textbooks on quantum physics. The author discusses a tradeoff between information on the actual path taken by the particle and the interference, thus concluding that complementarity can be viewed as a consequence of quantum entanglement.- The discussion of preferred states or pointer states that arise from environment-induced superselection. Discussions of superselection in textbooks on quantum physics typically do not discuss the topic in this manner.- The need for distinguishing between decoherence and dissipation, not only because of the purely quantum nature of decoherence but because of widely differing timescales over which these two phenomena occur.- The discussion on a scattering model, which even though does not take into account the formation of bound states, illustrates in fine detail the need for a no-recoil assumption and the origin of a decoherence factor which represents the rate at which spatial coherences between two positions become locally suppressed. In this context the author also discusses the time dependence of interference terms in reduced density matrices, quantifying the rate at which spatial coherences over a distance interval are suppressed, the important notion of a decoherence timescale.- The excellent discussion on the master-equation formulations of decoherence, including the Lindblad master equations. These formulations have recently become very important in the context of free-space optical propagation of laser beams, and the clarity of the author’s treatment will help readers who may be interested free-space optics what role decoherence and entanglement actually have in laser beam propagation.- The calculational models for decoherence, which serve to reinforce intuition on decoherence and how to connect it with actual experiments on decoherence. The discussions on these experiments is somewhat terse but they effectively introduce the reader to the literature on these experiments.

This highly specialized book determinedly sticks to its proclaimed aim with the emphasis very decidedly on decoherence . The author has contributed significantly to the field and everything he does in the book is carefully referenced to a bibliography listing no fewer than 514 items , bringing it up to the year 2006 .Zurek's work is copiously referred to . You have a theoretical problem with decoherence it's a good bet Schlosshauer has been there .You will find the formal basis for decoherence analysis and calculation extensively worked out leading to master equations which are then applied to solve specific model problems .Quantum computation is discussed as a prime victim to decoherence .Relevance of decoherence to various interpretations of QM is discussed : hidden-variables theories do not fare well . The status of the measurement problem is critically reviewed : the problem is still there . There also is a chapter on experiments demonstrating decoherence in a controlled way . The descriptions are detailed though not self-contained . For an experimentalist's approach to fundamental quantum physics experiments one should look at an also recent though somewhat earlier book by Haroche & Raimond .Thoretical physicists working in this field will want this outstanding book on their shelves and the author on their mailing list .This reader is left with a question : is there or will there be a consistently information-theoretical approach to the quantum-to-classical transition ?And here's an idea for the publisher : start quoting your book prices in oil barrels .Alex TrierSantiago , ChileRetired university professor

Excellent book. The arguments are convincing, the reference list is vast, examples are shown, it is very well written. It summarizes decades of research on decoherence. It is really how classical phenomena emerge from the quantum description. The author explains why we don't perceive quantum effects in our everyday life.The book describes decoherence from scratch. Beginners may read it without seeking other sources. The advanced reader will find deeper discussion in the book's second part.It is a must-have for every physicist.

This book revises the fundamental interpretation of quantum mechanics focusing on the weaknesses of the canonical Copenaghen interpretation. The decoherence program is explained through the book not without useful and interesting remarks on the historical development and the state-of-the-art of the program. It's definetly the most understandble and enjoyble book on this subject, although there are probably just a couple of altrernatives. Very useful also to revise several quantum mechanics concepts and formalisms.

At places too wordy and not giving practical skills. However, I found this book entertaining. Recommend for physicists who look for a simple book about the subject.

Lots of intuition. Highly recommended for newcomers in the field of quantum dynamics, open quantum systems.

Very comprehensive introduction to decoherence.

perfect

Very well written. Schlosshauer takes you by the hand and shows you everything you need to know.