Dynamics Research Of Cold Atoms In Optical Lattices With Periodic Modulations

Study of cold atoms in optical lattices open a new way to investigate the complicated problems in condensed matter physics.In recent years,the progress of atomic cooling and laser modulation technology provide a good support for us to study this system.Optical lattice is easy to control, no impurity or defec-t, convenient measurement and can gradually be adjusted that makes it used to simulate complicated physical systems . Optical lattices system in the Bloch oscillation, Wannier Stark ladder, Landau-Zener tunneling, Bose - Einstein con-densation, quantum ratchet, quantum computation ,quantum coding and many other directions has broad application .This paper mainly investigate the influence of Landau-Zener tunneling on the atomic current in optical lattices with periodic external field.By simplifying the system to a two-band model, the atomic current is obtained by the Boltz-mann equations.We focus on three situations to discuss the influence of the Landau-Zener tunneling and periodic field on the atomic current. Numerical calculations show the atomic transient current would finally become the stable oscillation,which amplitude and average value can be adjusted by the Landau-Zener tunneling and the periodic external field , respectively. This research provide reference for us to study physics problems in optical lattices and can also be taken as an effective way to observe the Landau-Zener tunneling.