Please use this identifier to cite or link to this item: http://hdl.handle.net/1959.3/50078

Title

First-principles quantum dynamics in interacting Bose gases II: stochastic gauges

Author(s)

Deuar, P.;  Drummond, P. D.

Abstract

First principles simulations of the quantum dynamics of interacting Bose gases using the stochastic gauge representation are analysed. In a companion paper, we showed how the positive-P representation can be applied to these problems using stochastic differential equations. That method, however, is limited by increased sampling error as time evolves. Here, we show how the sampling error can be greatly reduced and the simulation time significantly extended using stochastic gauges. In particular, local stochastic gauges (a subset) are investigated. Improvements are confirmed in numerical calculations of single-, double- and multi-mode systems in the weak-mode coupling regime. Convergence issues are investigated, including the recognition of two modes by which stochastic equations produced by phase-space methods in general can diverge: movable singularities and a noise-weight relationship. The example calculated here displays wave-like behaviour in spatial correlation functions propagating in a uniform 1D gas after a sudden change in the coupling constant. This could in principle be tested experimentally using Feshbach resonance methods.

Publication type

Journal article

Source

Journal of Physics A: Mathematical and General, Vol. 39, no. 11 (2006), pp. 2723-2755

Publication year

2006

FOR Code(s)

0206 Quantum Physics

Publisher

Institute of Physics Publishing

ISSN

0305-4470

Publisher URL

http://dx.doi.org/10.1088/0305-4470/39/11/011

Copyright

Copyright © 2006 IOP Publishing.

Peer reviewed