Mott transition in bosonic systems: Insights from the variational approach

TL;DR

This paper investigates the Mott transition in bosonic Hubbard models across different dimensions using a variational wave function approach, revealing detailed insights into the transition and effects of long-range interactions.

Contribution

It introduces a highly accurate variational wave function for describing the superfluid-insulator transition in bosonic systems across all dimensions.

Findings

The variational wave function accurately captures the Mott transition.

Mapping quantum averages to a classical model provides new insights into the insulating phase.

Evidence suggests anomalous Mott transition scenarios with added long-range interactions.

Abstract

We study the Mott transition occurring for bosonic Hubbard models in one, two, and three spatial dimensions, by means of a variational wave function benchmarked by Green's function Monte Carlo calculations. We show that a very accurate variational wave function, constructed by applying a long-range Jastrow factor to the non-interacting boson ground state, can describe the superfluid-insulator transition in any dimensionality. Moreover, by mapping the quantum averages over such a wave function into the the partition function of a classical model, important insights into the insulating phase are uncovered. Finally, the evidence in favor of anomalous scenarios for the Mott transition in two dimensions are reported whenever additional long-range repulsive interactions are added to the Hamiltonian.