Bose-Fermi-Hubbard model at finite temperature

TL;DR

This paper investigates phase transitions in the Bose-Fermi-Hubbard model at finite temperatures using the self-consistent random phase approximation, focusing on hard-core bosons and transitions between superfluid, supersolid, and charge-ordered phases.

Contribution

It introduces a detailed analysis of phase transitions in the Bose-Fermi-Hubbard model at finite temperature using pseudospin formalism and the random phase approximation.

Findings

Transitions between phases can be first or second order depending on parameters

Density-density correlator calculated within RPA framework

Possibility of superfluid to supersolid phase transition

Abstract

The phase transitions at finite temperatures in the systems described by the Bose-Fermi-Hubbard model are investigated in this work in the framework of the selfconsistent random phase approximation. The case of the hard-core bosons is considered and pseudospin formalism is used. The density-density correlator is calculated in the random phase approximation and the possibilities of transitions from superfluid to supersolid phases are investigated. It is shown that the transitions between uniform and charge ordered phases can be of the second or the first order, depending on the system parameters.