Typicality-Based Variational Cluster Approach to Thermodynamic Properties of the Hubbard Model

TL;DR

This paper introduces a variational-cluster-approximation method based on thermal-pure-quantum states to efficiently compute thermodynamic properties of the Hubbard model, revealing temperature-dependent behaviors of key physical quantities.

Contribution

The paper presents a novel variational-cluster-approximation approach utilizing thermal-pure-quantum states for studying finite-temperature properties of strongly correlated systems.

Findings

Temperature dependence of single-particle excitation spectra

Entropy and specific heat behaviors

Order parameter evolution in antiferromagnetic phase

Abstract

We develop the variational-cluster-approximation method based on the thermal-pure-quantum-state approach and apply the method to the calculations of the thermodynamic properties of the Hubbard model, thereby obtaining the temperature dependence of the single-particle excitation spectra, entropy and specific heat, and order parameter of the antiferromagnetic phase efficiently. We thus demonstrate that the method developed here has a potential power for elucidating finite-temperature properties of strongly correlated electron systems.