Physical Review A
Master equation for a damped nonlinear oscillator
Fritz Haake, H. Risken, Craig M. Savage, Daniel F. Walls
Abstract
We derive and discuss the dissipative effects of a heat bath on a nonlinear oscillator, excluding very low temperatures [kT\ensuremath{\lesssim}(level width )] such that a Markovian master equation holds. For temperatures high enough for excited states of the oscillator to acquire noticeable thermal population we find the nonlinearity to have a drastic influence on transition rates and level shifts.