Superfluid to Mott-insulator transition in Bose-Hubbard models

TL;DR

This paper investigates the superfluid to Mott-insulator transition in Bose-Hubbard models across different dimensions using a variational wave function, revealing dimension-dependent behaviors and spectral features consistent with experimental observations.

Contribution

It introduces a variational approach to study the transition in Bose-Hubbard models across multiple dimensions, providing insights into spectral weight distribution and phase transition characteristics.

Findings

In 1D, results align with Berezinskii-Kosterlitz-Thouless transition.

In 2D and 3D, spectral weight shifts to high energies at the transition.

Spectral features match experimental data on Mott-Hubbard side-bands.

Abstract

We study the superfluid-insulator transition in Bose-Hubbard models in one-, two-, and three-dimensional cubic lattices by means of a recently proposed variational wave function. In one dimension, the variational results agree with the expected Berezinskii-Kosterlitz-Thouless scenario of the interaction-driven Mott transition. In two and three dimensions, we find evidences that, across the transition,most of the spectral weight is concentrated at high energies, suggestive of pre-formed Mott-Hubbard side-bands. This result is compatible with the experimental data by Stoferle et al. [Phys. Rev. Lett. 92, 130403 (2004)].