Physical review. B, Condensed matter
Dissipative quantum dynamics at surfaces: A nonlinear-coupling model
Shiwu Gao
Abstract
The recently developed Lindblad approach for quantum dynamics of an open system with linear dissipation has been extended to a model of nonlinear coupling. The coupling term ${H}_{i}={\ensuremath{\sum}}_{k}{C}_{k}{f(x)q}_{k}$ is an arbitrary function of the system coordinate, but remains to be linear in bath coordinates. A Lindblad master equation and its associated stochastic differential equation have been obtained. To study dissipative surface dynamics, a general form of $f(x)$ has been proposed. It is shown that such a nonlinear-coupling model is crucial to qualitatively describe gas-surface dynamics, when a gas molecule impinging or leaving a surface goes beyond the linear-coupling regime.