Observation of vortex formation in an oscillating trapped Bose-Einstein condensate

TL;DR

This paper reports the experimental observation of vortex formation in a Bose-Einstein condensate of rubidium-87 atoms, induced by oscillating excitations, revealing vortex dynamics and nucleation mechanisms.

Contribution

First observation of vortex formation in a BEC caused by oscillating trap excitations, highlighting vortex nucleation and dynamics.

Findings

Vortices are generated by external magnetic field oscillations.

Vortex number and position vary shot-to-shot, indicating intrinsic nucleation dynamics.

Vortex and anti-vortex formation are discussed as possible mechanisms.

Abstract

We report on the observation of vortex formation in a Bose-Einstein condensate of Rb-87 atoms. Vortices are generated by superimposing an oscillating excitation to the trapping potential introduced by an external magnetic field. For small amplitudes of the external excitation field we observe a bending of the cloud axis. Increasing the amplitude we observe formation of a growing number of vortices in the sample. Shot-to-shot variations in both vortex number and position within the condensed cloud are observed, probably due to the intrinsic vortex nucleation dynamics. We discuss the possible formation of vortices and anti-vortices in the sample as well as possible mechanisms for vortex nucleation.