Quantum measurements and decoherence. Models and phenomenology
The book under review is a nice and mathematically transparent exposition of the properties of decoherence and its role in the quantum measurement theory. Especially, the dynamics of the decoherence process is investigated. After reviewing the general concepts of the quantum measurement theory in Chapter 2, special attention is given to uncertainties induced in quantum measurement. It is shown in Chapter 3 that uncertainty relations are sufficient for explaining the loss of the interference pattern. Chapter 4 is devoted to continuous quantum measurements (both sharp and unsharp), and their connections with the quantum Zeno effect. The phenomenological approach allowing to describe the decoherence without treating the environment of the measured system is developed in Chapters 5 and 6. It is based on the restricted path integral, Schrödinger equation with a complex Hamiltonian, and stochastic Schrödinger equations. In Chapter 7 the phenomenological approach is applied to analyzing the energy of multi-level systems. In a subsequent chapter a fuzzy continuous quantum measurement of a two-level system is studied. Chapter 9 deals with the quantum Zeno effect in a passive setup, which is an example of a genuinely continuous measurement. In the light of the methods introduced in the previous chapters, the conceptual problems of quantum measurement are reviewed in Chapter 10. The book brings a new view of measurement problem, especially of the mesoscopic situation in which there is a small number of external degrees of freedom. The ideas in the book may find application to the measurement theory and quantum computing in the future.
scientific article; zbMATH DE number 1447425