Altman, E.Polkovnikov, A.Demler, EugeneHalperin, BertrandLukin, Mikhail2016-08-242005Altman, E., A. Polkovnikov, E. Demler, B. I. Halperin, and M. D. Lukin. 2005. “Superfluid-Insulator Transition in a Moving System of Interacting Bosons.” Physical Review Letters 95 (2) (July 6). doi:10.1103/physrevlett.95.020402.0031-9007http://nrs.harvard.edu/urn-3:HUL.InstRepos:27899420We 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.en-USJournal Article2016-08-2410.1103/physrevlett.95.020402