Free expansion of a Bose-Einstein condensate at the presence of a thermal cloud

TL;DR

This paper numerically studies how a thermal cloud influences the free expansion dynamics of a Bose-Einstein condensate, revealing that thermal components significantly alter the condensate's behavior during expansion.

Contribution

It introduces a numerical approach using the classical field approximation to analyze the impact of thermal clouds on condensate expansion at nonzero temperatures.

Findings

Thermal clouds modify the expansion dynamics of the condensate.

The radial and axial widths are affected by the presence of thermal components.

Results align with experimental observations.

Abstract

We investigate numerically the free-fall expansion of a $^{87}$Rb atoms condensate at nonzero temperatures. The classical field approximation is used to separate the condensate and the thermal cloud during the expansion. We calculate the radial and axial widths of the expanding condensate and find clear evidence that the thermal component changes the dynamics of the condensate. Our results are confronted against the experimental data.