Effective action approach to the p-band Mott insulator and superfluid transition

Abstract

Motivated by the recent experiment on p-orbital band bosons in optical lattices, we study theoretically the quantum phases of Mott insulator and superfluidity in two-dimensions. The system features a novel superfluid phase with transversely staggered orbital current at weak interaction, and a Mott insulator phase with antiferro-orbital order at strong coupling and commensurate filling. We go beyond mean field theory and derive from a microscopic model an effective action that is capable of describing both the p-band Mott insulating and superfluid phases in strong coupling. We further calculate the excitation spectra near the quantum critical point and find two gapless modes away from the tip of the Mott lobe but four gapless modes at the tip. Our effective theory reveals how the phase coherence peak builds up in the Mott regime when approaching the critical point. We also discuss the finite temperature phase transition of p-band superfluidity.

9+epsilon pages, 7 figures, one appendix added, accepted by Phys. Rev. A

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Cited by in corpus (19)

• Physics of higher orbital bands in optical lattices: a review
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• Observing Chiral Superfluid Order by Matter-Wave Interference
• Time reversal symmetry breaking of $p$-orbital bosons in a one-dimensional optical lattice
• Orbital optical lattices with bosons
• Complex and real unconventional Bose-Einstein condensations in high orbital bands
• Creation on demand of higher orbital states in a vibrating optical lattice
• Confined p-band Bose-Einstein condensates
• Exotic phases of interacting p-band bosons
• Formation and detection of a chiral orbital Bose liquid in an optical lattice
• Renormalization group analysis of $p$-orbital Bose-Einstein condensates in a square optical lattice
• Stability of $p$-orbital Bose-Einstein condensates in optical checkerboard and square lattices
• Stripe, checkerboard, and liquid-crystal ordering from anisotropic p-orbital Fermi surfaces in optical lattices
• Emergence of the Unconventional Type-II Nambu-Goldstone Modes with Topological Origin in Bose Superfluids
• Unconventional Bose-Einstein Condensation in a System of Two-species Bosons in the $p$-orbital Bands of a Bipartite Lattice
• Bose-Einstein condensation in a frustrated triangular optical lattice
• Manipulating Goldstone modes via the superradiant light in a bosonic lattice gas inside a cavity
• Phase diagram of strongly attractive $p$-orbital fermions on optical lattices
• $p$-band stability of ultracold atom gas in anharmonic optical lattice potential with large energy scales