Coherence Dynamics of Two Interacting Bosonic Modes in a Thermal Environment

¹ Department of Theoretical Physics, National Institute of Physics and Nuclear Engineering, 077125 Bucharest-Magurele, Romania
² Faculty of Physics, University of Bucharest, 077125 Bucharest-Magurele, Romania
³ Academy of Romanian Scientists, 3 Ilfov str., 050044 Bucharest, Romania

^★ e-mail: isar@theory.nipne.ro

Published online: 20 January 2020

Abstract

We describe the time evolution of the quantum coherence in an open system consisting of two coupled bosonic modes embedded in a thermal reservoir. We discuss the influence of the environment in terms of the covariance matrix for initial squeezed thermal states. The coherence is quantified using the relative entropy as a measure, and its dynamics is studied in the framework of the theory of open systems based on completely positive quantum dynamical semigroups. We show that the evolution of the quantum coherence strongly depends on the initial state of the system (squeezing parameter and thermal photon numbers), the parameters characterizing the thermal reservoir (temperature and dissipation coefficient) and the intensity of the coupling between the two modes.