Ultracold bosons in a synthetic periodic magnetic field: Mott phases and re-entrant superfluid-insulator transitions

Abstract

We study Mott phases and superfluid-insulator (SI) transitions of ultracold bosonic atoms in a two-dimensional square optical lattice at commensurate filling and in the presence of a synthetic periodic vector potential characterized by a strength $p$ and a period $l=qa$, where $q$ is an integer and $a$ is the lattice spacing. We show that the Schrödinger equation for the non-interacting bosons in the presence of such a periodic vector potential can be reduced to an one-dimensional Harper-like equation which yields $q$ energy bands. The lowest of these bands have either single or double minima whose position within the magnetic Brillouin zone can be tuned by varying $p$ for a given $q$. Using these energies and a strong-coupling expansion technique, we compute the phase diagram of these bosons in the presence of a deep optical lattice. We chart out the $p$ and $q$ dependence of the momentum distribution of the bosons in the Mott phases near the SI transitions and demonstrate that the bosons exhibit several re-entrant field-induced SI transitions for any fixed period $q$. We also predict that the superfluid density of the resultant superfluid state near such a SI transition has a periodicity $q$ ($q/2$) in real space for odd (even) $q$ and suggest experiments to test our theory.

8 pages, 11 figures, v1

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Cited by in corpus (8)

• Quantum phase transition of ultracold bosons in the presence of a non-Abelian synthetic gauge field
• Superfluid-Insulator transition of two-species bosons with spin-orbit coupling
• Conductivity of strongly correlated bosons in optical lattices in an Abelian synthetic magnetic field
• Bosons with incommensurate potential and spin-orbit coupling
• Momentum Resolved Optical Lattice Modulation Spectroscopy for Bose Hubbard Model
• Thermal transitions of the modulated superfluid for spin-orbit coupled correlated bosons in an optical lattice
• Study of unconventional superfluid phases and the phase dynamics in spin-orbit coupled bose system
• Manipulating Goldstone modes via the superradiant light in a bosonic lattice gas inside a cavity