Repeated and continuous interactions in open quantum systems

Niveau: Supérieur, Master
Repeated and continuous interactions in open quantum systems Laurent Bruneau?, Alain Joye†‡, Marco Merkli¶ May 9, 2009 Abstract We consider a finite quantum system S coupled to two environments of different nature. One is a heat reservoir R (continuous interaction) and the other one is a chain C of independent quantum systems E (repeated interaction). The interactions of S with R and C lead to two simultaneous dynamical processes. We show that for generic such systems, any initial state approaches an asymptotic state in the limit of large times. We express the latter in terms of the resonance data of a reduced propagator of S + R and show that it satisfies a second law of thermodynamics. We analyze a model where both S and E are two-level systems and obtain the asymptotic state explicitly (lowest order in the interaction strength). Even though R and C are not direcly coupled, we show that they exchange energy, and we find the dependence of this exchange in terms of the thermodynamic parameters. We formulate the problem in the framework of W ?-dynamical systems and base the analysis on a combination of spectral deformation methods and repeated interaction model techniques. We do not use master equation approximations. 1 Introduction Over the last years, the rigorous study of equilibrium and non-equilibrium quantum systems has received much and renewed attention. While this topic of fundamental interest has a long tradition in physics and mathematics, conventionally explored via master equations [9, 6], dynamical semi-groups [3, 6] and algebraic scattering theory [32

• resonance approach


• quantum noise


• interaction


• arbitrary continuous


• observable algebra


• bj ?


• equilibrium quantum