paper

Extended Bose-Hubbard model in a shaken optical lattice

arXiv:1506.04539 · doi:10.1103/PhysRevA.92.023632

Abstract

We study an extended Bose-Hubbard model with next-nearest-neighbor (NNN) hopping in a shaken optical lattice. We show how mean-field phase diagram evolves with the change of NNN hopping amplitude , which can be easily tuned via shaking amplitude. As increases, a -symmetry-breaking superfluid (SF) phase emerges at the bottom of the Mott lobs. The tricritical points between normal superfluid, SF, and Mott insulator (MI) phases are identified. We further demonstrate the tricritical point can be tuned to the tip of the Mott lobe, in which case a new critical behavior has been predicted. Within random-phase approximation, excitation spectra in the three phases are obtained, which indicate how the phase transitions occur.

6 pages, 6 figures

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