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Superfluid-insulator transition in a moving system of interacting bosons

E. Altman·A. Polkovnikov·E. Demler·B. Halperin·M. D. Lukin
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Abstract

We analyze stability of superfluid currents in a system of strongly interacting ultra-cold 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.

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E. Altman, A. Polkovnikov, E. Demler, B. Halperin, M. D. Lukin. 2005-04-12. Superfluid-insulator transition in a moving system of interacting bosons. https://doi.org/10.1103/physrevlett.95.020402

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