Exact dynamics and thermalization of an open bosonic quantum system in the presence of a quantum phase transition induced by the environment
1 James Franck Institute and Department of Physics, University of Chicago - Chicago, IL 60637, USA
2 Laboratoire de Physique Théorique et Hautes Energies, Université Pierre et Marie Curie - Paris VI 4 Place Jussieu, 75252 Paris Cedex 05, France
Received: 26 August 2013
Accepted: 4 December 2013
We derive the exact out-of-equilibrium Wigner function of a bosonic mode linearly coupled to a bosonic bath of arbitrary spectral density. Our solution does not rely on any master equation approach and it therefore also correctly describes a bosonic mode which is initially entangled with its environment. It has been recently suggested that non-Markovian quantum effects lead to dissipationless dynamics in the case of a strong coupling to a bath whose spectral density has a support bounded from below. We show in this work that such a system undergoes a quantum phase transition at some critical bath coupling strength. The apparent dissipationless dynamics then correspond to the relaxation towards the new ground state.
PACS: 03.65.Yz – Decoherence; open systems; quantum statistical methods / 03.65.Ta – Foundations of quantum mechanics; measurement theory / 05.70.Ln – Nonequilibrium and irreversible thermodynamics
© EPLA, 2013