Exotic phases of interacting p-band bosons

TL;DR

This paper investigates a complex model of interacting p-band bosons in a 2D optical lattice, revealing novel superfluid phases with non-zero momentum condensation and orbital order, including a transition between staggered and striped superfluids.

Contribution

It introduces a detailed model capturing non-trivial superfluid phases and orbital order in p-band bosons, extending beyond the single band Bose-Hubbard framework.

Findings

Observation of staggered orbital angular momentum order in the Mott phase

Identification of a transition between staggered and striped superfluid phases

Qualitative agreement with recent experimental results

Abstract

We study a model of interacting bosons that occupy the first excited p-band states of a two-dimensional optical lattice. In contrast to the much studied single band Bose-Hubbard Hamiltonian, this more complex model allows for non-trivial superfluid phases associated with condensation at non-zero momentum and staggered order of the orbital angular momentum in addition to the superfluid-Mott insulator transition. More specifically, we observe staggered orbital angular momentum order in the Mott phase at commensurate filling and superfluidity at all densities. We also observe a transition between the staggered angular momentum superfluid phase and a striped superfluid, with an alternation of the phase of the superfluid along one direction. The transition between these two phases was observed in a recent experiment, which is then qualitatively well described by our model.