Stochastic longevity of a dark soliton in a finite-temperature Bose-Einstein condensate

TL;DR

This paper analytically and numerically investigates the decay dynamics of dark solitons in finite-temperature Bose-Einstein condensates, revealing thermal fluctuations can extend soliton lifetime.

Contribution

It provides an analytical expression for soliton decay time without thermal noise and demonstrates how thermal fluctuations influence soliton longevity.

Findings

Thermal fluctuations slow soliton decay at low temperatures.

Analytical lower bound for soliton decay time is derived.

Good agreement between theory and numerical simulations at low temperatures.

Abstract

We study the decay of a dark soliton in a homogeneous Bose-Einstein condensate. We give an analytical treatment of a decaying soliton, deriving an expression for the soliton velocity and decay time in the absence of thermal noise. We test the result against numerical simulations of a spatially confined system and find good agreement in the regime of low temperature ($k_BT\ll \mu$). Thermal fluctuations are found to slow the escape of the soliton, extending its lifetime beyond the predictions of the noise-free theory; the effect becomes significant at a characteristic temperature $k_BT\sim \mu$. This stabilization by noise allows us to infer an analytical lower bound for the dark soliton decay time.