Landau-Zener Tunnelling of Two-Component Bose-Einstein Condensates in Optical Lattices

T.F. Xu, C.S. Liu

姜欣, 林麦麦, 栗生长 +1 more

Guan-Qiang Li

We investigate the Landau–Zener tunnelling of two-component Bose-Einstein condensates (BECs) in optical lattices. In the neighborhood of the Brillouin zone edge, the system can be reduced to two coupled nonlinear two-level models. From the models, we calculate the change of the tunnelling probability for each component with the linear sweeping rate. It is found that the probability for each component exhibits regular oscillating behavior for the larger sweeping rate, but for smaller rate the oscillation is irregular. Moreover, the asymmetry of the tunnelling between the two components can be induced by the unbalanced initial populations or the inequality of the two self-interactions when the cross-interaction between the components exists. The result can not be found in the single component BECs.

O. Morsch

E. Arimondo, D. Ciampini, O. Morsch

We present our experimental investigations on the subject of nonlinearity-modified Bloch-oscillations and of nonlinear Landau-Zener tunneling between two energy bands in a rubidium Bose Einstein condensate in an accelerated periodic potential. Nonlinearity introduces an asymmetry in Landau-Zener tunneling. We also present measurements of resonantly enhanced tunneling between the Wannier-Stark energy levels for Bose-Einstein condensates loaded into an optical lattice.

Xi Yu-Dong, Denglong Wang, She Yan-Chao +3 more

With considering Bose-Einstein condensates to be confined in a periodic dichromatic optical lattice, Bloch energy band structure and Landau-Zener tunneling behaviors of the first and second band gaps are studied in this paper. It is shown that when the relative phase between the two lattices increases from 0 to π, the width of the first band gap in the Bloch energy band increases, while the width of the second band gap decreases. Meanwhile, it is found that the depth and the relative phase between the two lattices have both an important effect on Landau-Zener tunneling properties.