First-order superfluid-Mott insulator transition of spinor bosons in an optical lattice

TL;DR

This paper investigates the phase transition of spin-1 bosons in an optical lattice, revealing a first-order superfluid-Mott insulator transition that differs from the spinless case, with potential experimental observation.

Contribution

It demonstrates that the superfluid-Mott insulator transition for spin-1 bosons can be first-order, unlike the continuous transition in spinless bosons, using a variational Gutzwiller approach.

Findings

First-order transition identified at part of the phase boundary.

Transition can be observed experimentally with magnetic field techniques.

Contrasts with the spinless boson case where the transition is continuous.

Abstract

We study the superfluid-Mott insulator transition of antiferromagnetic spin-1 bosons in an optical lattice described by a Bose-Hubbard model. Our variational study with the Gutzwiller-type trial wave function determines that the superfluid-Mott insulator transition is a first-order one at a part of the phase boundary curve, contrary to the spinless case. This first-order transition may be observed through an experiment, such as a Stern-Gerlach type, under a magnetic field.