Dynamics of a single vortex line in a BoseEinstein condensate.pdfVIP

Dynamics of a single vortex line in a Bose-Einstein condensate P. Rosenbusch, V. Bretin, and J. Dalibard ∗ Laboratoire Kastler Brossel , 24 rue Lhomond, 75005 Paris, France (Dated: Received June 26, 2002) 2 We study experimentally the line of a single quantized vortex in a rotating prolate Bose-Einstein 0 condensate confined by a harmonic potential. In agreement with predictions, we find that the vortex 0 line is in most cases curved at the ends. We monitor the vortex line leaving the condensate. Its 2 length is measured as a function of time and temperature. For a low temperature, the survival time n can be as large as 10 seconds. The length of the line and its deviation from the center of the trap u are related to the angular momentum per particle along the condensate axis. J 7 PACS numbers: 03.75.Fi,32.80.Pj,67.40.Vs 2 ] The macroscopic motions of quantum and classical flu- Our 87Rb condensate is formed by radio-frequency h ids are dramatically different. The description of a quan- (rf) evaporation of 109 atoms in a Ioffe-Pritchard mag- √ c iθ e tum fluid by a macroscopic wave function = ρ e netic trap. The atoms are spin-polarized in the F = m imposes strong constraints upon its velocity field. At a mF = 2 state. The magnetic trap has a longitudinal