title: Bosonic Mott insulator with Meissner currents.
abstract: We introduce a generic bosonic model exemplifying that (spin) Meissner currents can persist in insulating phases of matter. We consider two species of interacting bosons on a lattice. Our model exhibits separation of charge (total density) and spin (relative density): the charge sector is gapped in a bosonic Mott insulator phase with total density one, while the spin sector remains superfluid due to interspecies conversion. Coupling the spin sector to the gauge fields yields a spin Meissner effect reflecting the long-range spin superfluid coherence. 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.
authors.affiliation: Department of Physics, Yale University, New Haven, Connecticut 06520, USA and Centre de Physique Théorique, École Polytechnique, CNRS, 91128 Palaiseau Cédex, France.
authors.forename: Alexandru
authors.initials: A
authors.lastname: Petrescu
authors.forename: Karyn
authors.initials: K
authors.lastname: Le Hur