A NOVEL METHOD FOR SIMULATING QUANTUM DISSIPATIVE SYSTEMS

An effective and flexible numerical scheme is proposed to simulate the dissipative quantum dynamics of a linearized system-bath Hamiltonian. Based on the observation that the Feynman path integrals for a Gaussi an bath have a quadratic functional form, the bath average can be perf ormed by directly sampling paths of the discretized harmonic modes and then propagating the system under the influence of quantum Gaussian f orce. The algorithm is amenable to all known quantum propagation metho ds and can thus be flexibly applied to study quantum dissipation in th e condensed phase. Nontrivial numerical examples based on the spin-bos on and damped quantum oscillator models are presented to demonstrate t he application of the new algorithm. (C) 1996 American Institute of Ph ysics.