Superfluid to Mott-insulator transition in an anizotropic two--dimensional optical lattice

TL;DR

This paper analyzes the superfluid to Mott-insulator transition in a two-dimensional optical lattice with anisotropy, providing an analytical phase diagram for various lattice geometries using the Bose-Hubbard model.

Contribution

It introduces an analytical description of the phase transition in anisotropic 2D lattices, extending understanding across different lattice geometries from square to quasi-one-dimensional.

Findings

Analytical phase diagram for superfluid to Mott-insulator transition.

Quantitative description of Mott lobes evolution with anisotropy.

Application to various lattice geometries from square to quasi-one-dimensional.

Abstract

We study the superfluid to Mott-insulator transition of bosons in an optical anizotropic lattice by employing the Bose-Hubbard model living on a two-dimensional lattice with anizotropy parameter $\kappa$. The compressible superfluid state and incompressible Mott-insulator (MI) lobes are efficiently described analytically, using the quantum U(1) rotor approach. The ground state phase diagram showing the evolution of the MI lobes is quantified for arbitrary values of $\kappa$, corresponding to various kind of lattices: from square, through rectangular to almost one-dimensional.