Direct observation of irrotational flow and evidence of superfluidity in a rotating Bose-Einstein condensate
(2001)
Calculation of mode coupling for quadrupole excitations in a Bose-Einstein condensate
(2001)
Temperature Dependence of Damping and Frequency Shifts of the Scissors Mode of a Trapped Bose-Einstein Condensate
Physical Review Letters American Physical Society (APS) 86:18 (2001) 3938-3941
Experimental observation of Beliaev coupling in a Bose-Einstein condensate.
Phys Rev Lett 86:11 (2001) 2196-2199
Abstract:
We report the first experimental observation of Beliaev coupling between collective excitations of a Bose-Einstein condensed gas. Beliaev coupling is not predicted by the Gross-Pitaevskii equation and so this experiment tests condensate theory beyond the mean field approximation. Measurements of the amplitude of a high frequency scissors mode show that the Beliaev process transfers energy to a lower-lying mode and then back and forth between these modes, unlike Landau processes which lead to a monotonic decrease in amplitude. To enhance the Beliaev process we adjusted the geometry of the magnetic trapping potential to give a frequency ratio of 2 to 1 between the two scissors modes.Temperature Dependence of Damping and Frequency Shifts of the Scissors Mode of a trapped Bose-Einstein Condensate
(2001)