EXPLICIT EXAMPLES OF DISSIPATIVE SYSTEMS IN THE QUANTUM STATE DIFFUSION-MODEL

The quantum state diffusion model describes the evolution of an indivi dual open quantum system by an Ito diffusion equation. In this paper w e show two examples of open systems which can be analytically treated, the damped harmonic oscillator and a pumped two-level system with spo ntaneous emission. The coherent states of the oscillator remain cohere nt through the stochastic evolution and undergo a classical Ornstein-U hlenbeck process. We also consider time correlation spectra of the sol utions of these stochastic equations.