Wednesday, June 26, 2013

1306.5986 (Alexandru Petrescu et al.)

Bosonic Mott Insulator with Meissner Currents    [PDF]

Alexandru Petrescu, Karyn Le Hur
We introduce a generic bosonic model exemplifying that (spin) Meissner currents can persist in insulating phases of matter, such as the Mott insulator. We consider two species of interacting bosons on a lattice. Our model exhibits separation of the charge (total density) and spin (relative density) degrees of freedom. The charge sector is gapped in a bosonic Mott insulator phase with total density one. At the same time, the spin sector remains superfluid, due to interspecies conversion which acts as a Josephson term. Coupling the spin sector to the gauge fields then yields a spin Meissner effect reflecting the long-range spin superfluid coherence. Applying a mixture of analytical and numerical methods, we investigate the resulting phase diagram and describe other possible spin phases of matter in the Mott regime possessing chiral currents as well as a spin-density wave phase. The model presented here is realizable in Josephson junction arrays and in cold atom experiments.
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