Fast rotation of a Bose-Einstein condensate.

We study the rotation of a 87Rb Bose-Einstein condensate confined in a quadratic plus quartic potential. This trap configuration allows one to increase the rotation frequency of the gas above the trap frequency. In such a fast rotation regime we observe a dramatic change in the appearance of the quantum gas. The vortices which were easily detectable for a slower rotation become much less visible, and their surface density is well below the value expected for this rotation frequency domain. We discuss some possible tracks to account for this effect.

[1]  C. E. Wieman,et al.  Vortices in a Bose Einstein condensate , 1999, QELS 2000.

[2]  Sandro Stringari,et al.  Macroscopic dynamics of a Bose-Einstein condensate containing a vortex lattice , 2003 .

[3]  T L Ho.  Bose-Einstein condensates with large number of vortices. , 2001, Physical review letters.

[4]  Masahito Ueda,et al.  Giant hole and circular superflow in a fast rotating Bose-Einstein condensate , 2002 .

[5]  G. Baym,et al.  Rapidly rotating Bose-Einstein condensates in anharmonic potentials , 2002, cond-mat/0212596.

[6]  O M Maragò,et al.  Vortex nucleation in Bose-Einstein condensates in an oblate, purely magnetic potential. , 2002, Physical review letters.

[7]  Russell J. Donnelly,et al.  Quantized Vortices in Helium II , 1991 .

[8]  Y. Castin,et al.  Bose-Einstein condensates with vortices in rotating traps , 1999 .

[9]  I Coddington,et al.  Observation of long-lived vortex aggregates in rapidly rotating Bose-Einstein condensates. , 2003, Physical review letters.

[10]  W. Ketterle,et al.  Observation of Vortex Lattices in Bose-Einstein Condensates , 2001, Science.

[11]  N. Regnault,et al.  Quantum Hall fractions in rotating Bose-Einstein condensates. , 2002, Physical review letters.

[12]  J Dalibard,et al.  Stationary states of a rotating Bose-Einstein condensate: routes to vortex nucleation. , 2001, Physical review letters.

[13]  Castin,et al.  Bose-Einstein Condensates in Time Dependent Traps. , 1996, Physical review letters.

[14]  D S Petrov,et al.  Critical rotation of a harmonically trapped Bose gas. , 2002, Physical review letters.

[15]  W. Ketterle,et al.  Vortex nucleation in a stirred Bose-Einstein condensate. , 2001, Physical review letters.

[16]  J Dalibard,et al.  Dynamics of a single vortex line in a Bose-Einstein condensate. , 2002, Physical review letters.

[17]  Dalibard,et al.  Measurement of the angular momentum of a rotating bose-einstein condensate , 2000, Physical review letters.

[18]  S. Stringari,et al.  Quantized Vortices and Collective Oscillations of a Trapped Bose-Einstein Condensate , 1998, cond-mat/9805068.

[19]  I Coddington,et al.  Nonequilibrium effects of anisotropic compression applied to vortex lattices in bose-einstein condensates. , 2002, Physical review letters.

[20]  Quantum melting and absence of Bose-Einstein condensation in two-dimensional vortex matter. , 2002, Physical review letters.

[21]  N R Cooper,et al.  Quantum phases of vortices in rotating Bose-Einstein condensates. , 2001, Physical review letters.

[22]  Dalibard,et al.  Vortex formation in a stirred bose-einstein condensate , 1999, Physical review letters.

[23]  I Coddington,et al.  Driving Bose-Einstein-condensate vorticity with a rotating normal cloud. , 2001, Physical review letters.

[24]  I Coddington,et al.  Rapidly rotating Bose-Einstein condensates in and near the lowest Landau level. , 2003, Physical review letters.

[25]  Reynolds,et al.  Kinetic theory of the evaporative cooling of a trapped gas. , 1996, Physical review. A, Atomic, molecular, and optical physics.

[26]  C. J. Pethick,et al.  Vortices in Bose-Einstein-condensed atomic clouds , 1998 .

[27]  Gordon Baym,et al.  Vortex states of rapidly rotating dilute Bose-Einstein condensates. , 2003, Physical review letters.

[28]  N. J. Druten,et al.  Evaporative Cooling of Trapped Atoms , 1996 .

[29]  J. Cirac,et al.  1/2-anyons in small atomic Bose-Einstein condensates. , 2001, Physical review letters.

[30]  E. Lundh.  Multiply quantized vortices in trapped Bose-Einstein condensates , 2001, cond-mat/0103272.

[31]  Rotating vortex lattice in a Bose-Einstein condensate trapped in combined quadratic and quartic radial potentials , 2001, cond-mat/0109418.