Photo-induced waves of the Bose condensate in optical superlattices

The dynamics of ultracold atoms loaded in an optical lattice (superlattice) is described in the article on the basis of the Bose–Hubbard model. Both linear and circular lattices are considered in terms of attractive and repulsive types of interaction between the bosons. The numerically observed quantum-mechanical current state of the Bose condensate atoms is due to a hopping transfer of the ultracold atoms caused by the excitation of the system by the biharmonic electromagnetic field under the Raman resonance condition. When the energy of interaction between the bosons is close to the energy of photoactivation, the boson current decreases, which may be the sign of the superfluidity-insulator phase transition. In the disordered linear chain of potentials, where the depth of optical potentials alters from one site to another, the current spreading over the sites of optical lattice is suppressed in the same way as in the Anderson localization effect.