Chiral orbital order of interacting bosons without higher bands

Abstract

Ultracold atoms loaded into higher Bloch bands provide an elegant setting for realizing many-body quantum states that spontaneously break time-reversal symmetry through the formation of chiral orbital order. The applicability of this strategy remains nonetheless limited due to the finite lifetime of atoms in high-energy bands. Here we introduce an alternative framework, suitable for bosonic gases, which builds on assembling square plaquettes pierced by a $\pi$-flux (half a magnetic-flux quantum). This setting is shown to be formally equivalent to an interacting bosonic gas loaded into $p$ orbitals, and we explore the consequences of the resulting chiral orbital order, both for weak and strong onsite interactions. We demonstrate the emergence of a chiral superfluid vortex lattice, exhibiting a long-lived gapped collective mode that is characterized by local chiral currents. This chiral superfluid phase is shown to undergo a phase transition to a chiral Mott insulator for sufficiently strong interactions. Our work establishes coupled $\pi$-flux plaquettes as a practical route for the emergence of orbital order and chiral phases of matter.

4+3 pages, 4+2 figures

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Cited by in corpus (9)

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• Recent progress on quantum simulations of non-standard Bose-Hubbard models
• Floquet engineering of optical nonlinearities: a quantum many-body approach
• Floquet-engineered nonlinearities and controllable pair-hopping processes: From optical Kerr cavities to correlated quantum matter
• Floquet-engineered Emergent Massive Nambu-Goldstone Modes
• Many-body phases from effective geometrical frustration and long-range interactions in a subwavelength lattice
• Chiral phases and dynamics of dipoles in triangular optical ladders
• Fate of chiral order and impurity self-pinning in flat bands with local symmetry
• Vortex bound states in dimerized $\pi$-flux optical lattices: characterization, state preparation and current measurement