Generalized Caldeira-Leggett system plus reservoir model

Interaction between system and reservoir is considered to be linear in the coordinates of heat bath but nonlinear in the system coordinate and velocity. The reduced partition function of the system is presented and the corresponding effective classical potential is calculated by using the path-integral Monte Carlo method. In the presence of the nonlinear coupling, a dissipative threshold is observed at finite temperatures, and the decay rate of a particle in a metastable potential can be hindered by inhomogeneous dissipation above twice the crossover temperature.