Rotating condensates put new spin on superfluidity. (News Briefs).

Scientists at NIST have been studying the behavior of Bose-Einstein condensates subject to rotation of the trap, which is a key issue in the phenomenon of superfluidity. When the trap is subject to a low rate of rotation, the condensate does not exhibit any net circulation, unlike a classical fluid that will circulate with the trap. Nevertheless, the condensate does acquire some angular momentum, which results in an anisotropic density distribution.

NIST scientists had the simple theoretical insight that when a condensate is released from a rotating trap it flies apart under conditions in which angular momentum is conserved, preserving the anisotropy in the density distribution. This effect is simple to observe and possible to test with considerable quantitative accuracy. An experimental group at Oxford University, having received a preprint of the NIST paper, performed the experiment and confirmed the theoretical predictions. The theoretical and experimental papers were published simultaneously in the February 11, 2002, issue of Physical Review Letters.

CONTACT: Charles Clark, [phone]; [e-mail].