Thermodynamics of a Modified Fermi-Hubbard Model

TL;DR

This paper explores a modified Fermi-Hubbard model using a recurrence-relation ansatz to calculate thermodynamic properties, revealing phase transitions and comparing constrained and unconstrained cases.

Contribution

It introduces a solvable variant of the Fermi-Hubbard model with a new ansatz, analyzing thermodynamics and phase transitions under density constraints.

Findings

Identifies a second-order phase transition similar to quantum Hall effects.

Discovers a first-order phase transition in the ground state.

Provides thermodynamic observables for the modified model.

Abstract

A recently introduced recurrence-relation ansatz applied to the Fermi-Hubbard model gives rise to a soluble model and here is used to calculate several thermodynamic observables. The constraint of unit density per site, density = 1, is applied and some of the results are compared to cases where the constraint is not imposed. The modified model exhibits a continuous phase transition (second order) reminiscent of the integer quantum Hall resistance and a ground state, first-order phase transition.