A model of Josephson Junctions on Boson Systems - Currents and Entropy Production Rate -

Abstract

Non-equilibrium steady states (NESS), in the sense of D. Ruelle, of Boson systems with Bose--Einstein condensation (BEC) are investigated with the aid of the C^*-algebraic method. The model consists of a quantum particle and several bosonic reservoirs. We show that the mean entropy production rate is strictly positive, independent of phase differences provided that the temperatures or the chemical potentials of reservoirs are different. Moreover, Josephson currents occur without entropy production, if the temperatures and the chemical potentials of reservoirs are identical.