Eur. Phys. J. D 29, 105-118 (2004)
https://doi.org/10.1140/epjd/e2004-00010-x

The non-Markovian quantum behavior of open systems

An exact Monte Carlo method employing stochastic product states

¹ Physikalisches Institut, Universität Freiburg, 79104 Freiburg, Germany
² Institut für Physik, Carl von Ossietzky Universität, 26111 Oldenburg, Germany

Corresponding author: ^a breuer@physik.uni-freiburg.de

Received: 29 October 2003
Published online: 10 February 2004

Abstract

It is shown that the exact dynamics of a composite quantum system can be represented through a pair of product states which evolve according to a Markovian random jump process. This representation is used to design a general Monte Carlo wave function method that enables the stochastic treatment of the full non-Markovian behavior of open quantum systems. Numerical simulations are carried out which demonstrate that the method is applicable to open systems strongly coupled to a bosonic reservoir, as well as to the interaction with a spin bath. Full details of the simulation algorithms are given, together with an investigation of the dynamics of fluctuations. Several potential generalizations of the method are outlined.