Superfluid-Insulator Transition in a Moving System of Interacting Bosons

Ehud Altman, Anatoli Polkovnikov, Eugene Demler +2 more

Jereson Silva-Valencia, André M. C. Souza

Laurent Sanchez-Palencia

Zhengwei Xie, Weixi Liu

The superfluid--Mott-insulator phase transition of dipolar bosons in optical lattice is analyzed. By using the Bogoliubov approach and decoupling approximation, the energy spectrum and zero-temperature phase diagram of dipolar bosonic atoms in an optical lattice are obtained analytically. The results show that in these systems the superfluid--Mott-insulator phase transition can be induced by tuning the dipole-dipole interaction and the position of the phase boundary can be moved when the on-site interaction is varied. Corresponding to a large on-site interaction, the dipole-dipole interaction is attractive near the critical point of the superfluid--Mott-insulator phase transition.

Nandini Trivedi, Salman Ullah

Ehud Altman, Anatoli Polkovnikov, Eugene Demler +2 more

We analyze the stability of superfluid currents in a system of strongly interacting ultracold atoms in an optical lattice. We show that such a system undergoes a dynamic, irreversible phase transition at a critical phase gradient that depends on the interaction strength between atoms. At commensurate filling, the phase boundary continuously interpolates between the classical modulation instability of a weakly interacting condensate and the equilibrium quantum phase transition into a Mott insulator state at which the critical current vanishes. We argue that quantum fluctuations smear the transition boundary in low dimensional systems. Finally we discuss the implications to realistic experiments.