QUANTUM TUNNELING OF BOSE-EINSTEIN CONDENSATES IN OPTICAL LATTICES
Fan Wen
Abstract
Abstract In quantum tunneling a particle with energy E can pass through a high potential barrier V(E) due to the wave character of the particle. Bose\|Einstein condensates can display very strong tunneling depending on the structure of the trap, which may be a double\|well or optical lattices. We employed for the first time to our knowledge the periodic instanton method to investigate tunneling of Bose\|Einstein condensates in optical lattices. Our results show that there are two kinds of tunneling in this system, Landau\|Zener tunneling between extended states of the system and Wannier\|Stark tunneling between localized states of the system, and that the latter is 1000 times faster than the former. We also obtain the total decay rate for a wide range of temperature, including classical thermal activation, thermally assisted tunneling and quantum tunneling. Our results agree with experimental data in references[1, 2].Finally, we propose an experimental protocol to observe this new phenomenon in future experiments. periodic instanton, Wannier\|Stark localization, Landau\|Zener tunneling, Wannier\|Stark tunneling