Abstract

We report experimental results on transport properties of Bose-Einstein condensates in periodic optical potentials of variable asymmetry. By studying the Landau-Zener effect and Bloch oscillations, we have explored the band structure of both ratchet-type asymmetric and symmetric optical potentials. In earlier work, quantum transport in “conventional” sinusoidal lattices has proven to be a powerful technique for characterisation of the band structure. To realize lattice potentials of variable asymmetry, we superimpose the conventional lattice potential of λ /2 spatial periodicity with a fourth-order optical potential of λ/4 spatial periodicity. The high periodicity lattice is realized using despersive properties of multiphoton Raman transitions[l]. To study quantum transport in such Fourier-synthesized lattice potentials the periodic potential is accelerated.

© 2007 IEEE