Free-fall expansion of finite-temperature Bose-Einstein condensed gas in the non Thomas-Fermi regime

TL;DR

This paper investigates how finite-temperature effects influence the free-fall expansion of Bose-Einstein condensates, showing that thermal clouds compress the condensate and affect its dynamics.

Contribution

It provides experimental evidence of the interaction between thermal clouds and condensates during free-fall expansion in the non Thomas-Fermi regime.

Findings

Thermal cloud compresses the condensate during expansion.

Condensate dynamics depend on thermal interactions.

Experimental data supports non Thomas-Fermi regime behavior.

Abstract

We report on our study of the free-fall expansion of a finite-temperature Bose-Einstein condensed cloud of 87Rb. The experiments are performed with a variable total number of atoms while keeping constant the number of atoms in the condensate. The results provide evidence that the BEC dynamics depends on the interaction with thermal fraction. In particular, they provide experimental evidence that thermal cloud compresses the condensate.