title: Global stationary phase and the sign problem.
abstract: We present a computational strategy for reducing the sign problem in the evaluation of high dimensional integrals with nonpositive definite weights whose logarithms are analytic. The method involves stochastic sampling with a positive semidefinite weight that is adaptively and optimally determined during the course of a simulation. The optimal criterion, which follows from a variational principle for analytic actions S(z), is a global stationary phase condition that the average gradient of the phase ImS along the sampling path vanishes. Numerical results are presented from simulations of a model adapted from statistical field theories of classical fluids.
authors: Materials Research Laboratory, University of California, Santa Barbara, California 93106, USA.
authors: André G
authors: AG
authors: Moreira
authors: Stephan A
authors: SA
authors: Baeurle
authors: Glenn H
authors: GH
authors: Fredrickson