Concepts and methods in the theory of open quantum systems

Abstract

The central physical concepts and mathematical techniques used in the theory of open quantum systems are reviewed. Particular emphasis is laid on the interrelations of apparently different approaches. Starting from the appropriate characterization of the quantum statistical ensembles naturally arising in the description of open quantum systems, the corresponding dynamical evolution equations are derived for the Markovian as well as for the non-Markovian case.Comment: 15 pages, 7 figures, conference proceedings, to be published in: Irreversible Quantum Dynamics, Lecture Notes in Physics, F. Benatti and R. Floreanini (Eds