A method of solving the sign problem in the Monte Carlo path-integral simulations of quantum dynamics is presented. Our method is based on the distortion of integration contours in conjunction with a stationary-phase-filtering method. Using this importance sampling, correlation functions for the spin-boson model have been computed for real times much longer than βħ.

• Received 27 November 1989

DOI:https://doi.org/10.1103/PhysRevA.41.5709