Driving Bose-Einstein condensate vorticity with a rotating normal cloud
Abstract
We have developed an evaporative cooling technique that accelerates the circulation of an ultra-cold Rb gas, confined in a static harmonic potential. As a normal gas is evaporatively spun up and cooled below quantum degeneracy, it is found to nucleate vorticity in a Bose-Einstein condensate. Measurements of the condensate's aspect ratio and surface-wave excitations are consistent with effective rigid-body rotation. Rotation rates of up to 94% of the centrifugal limit are inferred. A threshold in the normal cloud's rotation is observed for the intrinsic nucleation of the first vortex. The threshold value lies below the prediction for a nucleation mechanism involving the excitation of surface-waves of the ground-state condensate.
Cite
@article{arxiv.cond-mat/0106362,
title = {Driving Bose-Einstein condensate vorticity with a rotating normal cloud},
author = {P. C. Haljan and I. Coddington and P. Engels and E. A. Cornell},
journal= {arXiv preprint arXiv:cond-mat/0106362},
year = {2009}
}
Comments
5 revtex pages, 3 embedded figures