Stochastic phase slips in toroidal Bose-Einstein condensates

TL;DR

This paper investigates how thermal noise affects phase slips in toroidal Bose-Einstein condensates with a rotating weak link, deriving a generalized rate expression and analyzing the energy barriers involved.

Contribution

The study introduces a generalized Arrhenius-like expression for stochastic phase slip rates and a method to estimate energy barriers in BECs, validated against deterministic dynamics.

Findings

Thermal noise lowers the phase-slip threshold.

The impact of stochastic phase slips is too small to explain experimental discrepancies.

Energy barriers vanish at critical parameters consistent with simulations.

Abstract

Motivated by recent experiments we study the influence of thermal noise on the phase slips in toroidal Bose-Einstein condensates with a rotating weak link. We derive a generalized Arrhenius-like expression for the rate of stochastic phase slips. We develop a method to estimate the energy barrier separating different superflow states. The parameters at which the energy barrier disappears agree with the critical parameters for deterministic phase slips obtained from dynamics simulations, which confirms the validity of our energetic analysis. We reveal that adding thermal noise lowers the phase-slip threshold. However, the quantitative impact of the stochastic phase slips turns out to be too small to explain the significant discrepancy between theoretical and the experimental results.