arXiv:cond-mat/0506466 · Laser Physics

Gutzwiller study of spin-1 bosons in an optical lattice under a magnetic field

T. Kimura, Shunji Tsuchiya, Makoto Yamashita, Susumu Kurihara

Published Jan 1, 2007• 1 citation

Abstract

We study spin-1 bosons in an optical lattice under a magnetic field with the Gutzwiller approximation for the Bose-Hubbard model. Phase boundary curves between superfluids and Mott insulators depend continuously on the magnetic field, and this provides better results than those obtained with the perturbative mean-field approximation. The phase boundary curve as a function of magnetic field has a sharp cusp structure under certain circumstances. In superfluid phases, both the spin magnetizations and fluctuations in the total number of bosons show strong magnetic field dependence, which is related to the fact that both first-and second-order transitions appear on the phase boundary curve according to the magnetic field.

DOI: 10.1134/s1054660x07010112

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arXiv:cond-mat/0506466 · Laser Physics

Gutzwiller study of spin-1 bosons in an optical lattice under a magnetic field

T. Kimura, Shunji Tsuchiya, Makoto Yamashita, Susumu Kurihara

Published Jan 1, 2007• 1 citation

arXiv HTML PDF

Abstract

DOI: 10.1134/s1054660x07010112

Related papers

Superfluid–Mott Insulator Transition of Spin-1 Bosons in Optical Lattice under Magnetic Field

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We investigate the superfluid--Mott-insulator quantum phase transition of spin-1 bosons in an optical lattice created by pairs of counterpropagating linearly polarized laser beams, driving an

{F}_{g}=1

{F}_{e}=1

internal atomic transition. The whole parameter space of the resulting two-component Bose-Hubbard model is studied. We find that the phase transition is not always second order as in the case of spinless bosons, but can be first order in certain regions of the parameter space. The calculations are done in the mean-field approximation by means of exact numerical diagonalization as well as within the framework of perturbation theory.

U_2>0

) and ferromagnetic (

U_2<0

) couplings, respectively.

XXZ

model in a transverse field and the numerical results compare very well with the analytical results obtained from the spin model. In the superfluid regime quantum fluctuations strongly modify the phase transition with respect to the well-established mean-field three-dimensional classical bifurcation.