WAVE-FUNCTION APPROACH TO DISSIPATIVE PROCESSES IN QUANTUM OPTICS

A novel treatment of dissipation of energy from a "small" quantum system to a reservoir is presented. We replace the usual master equation for the small-system density matrix by a wave function evolution including a stochastic element. This wave-function approach provides new insight and it allows calculations on problems which would otherwise be exceedingly complicated. The approach is applied here to a two- or three-level atom coupled to a laser field and to the vacuum modes of the quantized electromagnetic field.