Mott insulator to superfluid transition of ultracold bosons in an optical lattice near a Feshbach resonance

TL;DR

This paper explores the phase diagram of ultracold bosons in optical lattices near a Feshbach resonance, revealing multiple insulator-superfluid transitions influenced by density, lattice strength, and magnetic field tuning.

Contribution

It introduces a detailed analysis of phase transitions involving atomic and molecular condensates near a Feshbach resonance, highlighting multiple transition pathways.

Findings

Multiple insulator-superfluid transitions occur as magnetic field varies.

Ground state can be Mott insulator, atomic superfluid, or molecular superfluid.

Transitions can be driven by lattice strength or detuning changes.

Abstract

We study the phase diagram of ultracold bosons in an optical lattice near a Feshbach resonance. Depending on the boson density, the strength of the optical lattice potential and the detuning from resonance, the ground state can be a Mott insulator, a superfluid phase with both an atomic and a molecular condensate, or a superfluid phase with only a molecular condensate. Mott insulator to superfluid transitions can be induced either by decreasing the strength of the optical lattice potential or by varying the detuning from the Feshbach resonance. Quite generally, we find that for a commensurate density the ground-state may undergo several insulator-superfluid or superfluid-insulator transitions as the magnetic field is varied through the resonance.