The non-Markovian stochastic Schrodinger equation for open systems

We present the non-Markovian generalisation of the widely used stochastic Schrodinger equation. Our result allows one to describe open quantum systems in terms of stochastic state vectors rather than density operators, without Markov approximation. Moreover, it unifies two recent independent attempts towards a stochastic description of non-Markovian open systems, based on path integrals on the one hand and coherent states on the other. The latter approach utilises the analytical properties of coherent states and enables a microscopic interpretation of the stochastic states. The alternative first approach is based on the general description of open systems using path integrals as originated by Feynman and Vernon. (C) 1997 Elsevier Science B.V.