Free expansion of Bose-Einstein condensates with initially applied velocity fields

P. CAPUZZI; D. M. JEZEK

Foz do Iguazu

Workshop; 19th INTERNATIONAL LASER PHYSICS WORKSHOP; 2010

We investigate the evolution of the aspect ratio of freely expanding Bose-Einstein conden-sates initially carrying non-trivial velocity fields and after being confined by anisotropicpotentials. The analysis of the dynamics of the expansion permits us to characterize theinitial state of the system. By developing a simple numerical strategy we are able tostudy large expansion rates of the condensate governed by the Gross-Pitaevskii equation.We illustrate its application in two specific cases: a condensate obtained by applying anoff-axis spherical quadrupole oscillation for a period of time, and a condensate withan initial array of pinned vortices. We find that the final aspect ratio of the condensatemay noticeably deviate from the prediction of the scaling Thomas-Fermi theory and become closer to unity depending on the magnitude of the interaction energy and the anisotropy of the velocity field.