Landau and dynamical instabilities of the superflow of Bose-Einstein condensates in optical lattices
نویسندگان
چکیده
The superfluidity of Bose-Einstein condensates ~BECs! in optical lattices is investigated. Apart from the usual Landau instability, which occurs when a BEC flows faster than the speed of sound, the BEC can also suffer a dynamical instability, resulting in period doubling and other sorts of symmetry breaking of the system. Such an instability plays a crucial role in the dissipative motion of a trapped BEC in an optical lattice recently observed @Burger et al., Phys. Rev. Lett. 86, 4447 ~2001!#.
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