標題: Instabilities of Bose-Einstein condensates in optical lattices
作者: Kuan, W. H.
Jiang, T. F.
Cheng, Szu-Cheng
物理研究所
Institute of Physics
公開日期: 1-Apr-2007
摘要: We study the instabilities, Landau and dynamical instabilities, that are two mechanisms responsible for the breakdown of superfluidity in Bose-Einstein condensates interacting with a one-dimensional optical lattice. An effective-mass Gross-Pitaevskii equation was used to calculate the excitation spectrum and the condensate density of Bose-Einstein condensates in a weak periodic potential. After the condensate velocities greater than the speed of sound, we observe a decreasing of the condensate density, which is the onset of Landau instability. The condensate is dissipated, but not completely, from colliding with the thermal atom cloud. For even higher velocities of the condensate, we find a fast decreasing of the condensate density until full removal of the condensate. The regime of totally removing of the condensate is happened at the inverse effective mass of the condensate becoming zero or negative, where the condensate is on the dynamical instability.
URI: http://hdl.handle.net/11536/4894
ISSN: 0577-9073
期刊: CHINESE JOURNAL OF PHYSICS
Volume: 45
Issue: 2
起始頁: 219
結束頁: 229
Appears in Collections:Conferences Paper