Lecture Series in Condensed Matter and Statistical Physics II

 
Nonequilibrium Transport in Open Quantum Systems
Lecturer: Ali G. Moghaddam
Institute for Advanced Studies in Basic Sciences (IASBS) and IPM
12 November, 2014 (21 Aban 1393)
11:00-12:30 and 14:00-16:00
School of Physics, IPM, Tehran

When a quantum system interacts with an external system (the environment) its dynamics is not governed by unitary evolution in contrast to closed quantum systems and the so-called decoherence and dissipation effects come into play. The theory of open quantum systems addresses the problems of damping and dephasing in quantum systems by the assertion that all real systems of interest are "open" systems, surrounded by their environments. Based on many application in quantum optics, quantum measurement theory, quantum cosmology, and recently quantum electronics the theory of open quantum systems is developed a lot through the decades and is still improving. One of the main lines of the theory is to study transport phenomena in optical or electronic systems which are driven out of equilibrium. In these series of lectures, with special focus on solid state systems, an introduction about the theory of open quantum systems will be presented first. Then, we discuss the generalized master equation and approximation schemes in order to obtain the dynamics of system’s density matrix. The question of what information we can obtain about the system’s dynamics and how that is achieved will be answered. There are some limitations on the applicability of the theory, mostly originating from the approximations like Markov, Born, etc., which will be addressed in brief. Finally we will examine the techniques introduced for the study of electron tunneling through an interacting quantum dot as a prototype model of open quantum systems.