Dark soliton decay in a Bose-Einstein condensate

We consider the decay of a dark soliton in a homogeneous BEC at finite temperature, with a particular emphasis on the effect of thermal noise on the stability of the soliton. We present an analytical treatment of a damped soliton in an unbounded system, comparing the predicted dynamics with numerical stochastic simulations of a spatially confined system. By varying the system temperature we study the relative importance of noise on the motion of the soliton. In the regime of low temperature the soliton is largely immune to thermal fluctuations, and is well described by the damped Gross-Pitaevskii equation. In this regime our analytical treatment is in close agreement with numerical simulations. For sufficiently high temperature, the thermal fluctuations have the interesting effect of increasing the stability of the soliton, extending its lifetime beyond the predictions of damped Gross-Pitaevskii theory.