Quantum dynamics with stochastic gauge simulations

TL;DR

This paper introduces stochastic gauge representations as a flexible method for simulating quantum dynamics, offering positive-definite stochastic equations applicable to diverse quantum systems.

Contribution

It presents a novel stochastic gauge approach that generalizes traditional phase-space methods for quantum evolution simulations.

Findings

Stochastic gauges produce positive-definite equations for quantum systems.

Applicable to systems like molecular hydrogen and Bose-Einstein condensates.

Demonstrated with simple astrophysical and condensed matter examples.

Abstract

The general idea of a stochastic gauge representation is introduced and compared with more traditional phase-space expansions, like the Wigner expansion. Stochastic gauges can be used to obtain an infinite class of positive-definite stochastic time-evolution equations, equivalent to master equations, for many systems including quantum time-evolution. The method is illustrated with a variety of simple examples ranging from astrophysical molecular hydrogen production, through to the topical problem of Bose-Einstein condensation in an optical trap and the resulting quantum dynamics.