Solitons as the early stage of quasicondensate formation during evaporative cooling

TL;DR

This paper investigates the formation and dissipation of solitons during evaporative cooling of 1D Bose-Einstein condensates, linking soliton dynamics to the coherence length in the final thermal state.

Contribution

It provides a detailed calculation of soliton behavior during cooling, connecting phase defect formation with thermal fluctuations in a unified framework.

Findings

Solitons form during evaporation but dissipate during thermalization.

The soliton spacing matches the coherence length in the final state.

The classical fields method effectively models the cooling dynamics.

Abstract

We calculate the evaporative cooling dynamics of trapped one-dimensional Bose-Einstein condensates for parameters leading to a range of condensates and quasicondensates in the final equilibrium state. We confirm that solitons are created during the evaporation process, but always eventually dissipate during thermalisation. The distance between solitons at the end of the evaporation ramp matches the coherence length in the final thermal state. Calculations were made using the classical fields method. They bridge the gap between the phase defect picture of the Kibble-Zurek mechanism and the long-wavelength phase fluctuations in the thermal state.