Detecting phase transitions and crossovers in Hubbard models using the fidelity susceptibility

TL;DR

This paper demonstrates that fidelity susceptibility, calculated via dynamical mean-field theory and quantum Monte Carlo, is an effective and inexpensive tool for detecting various phase transitions and crossovers in Hubbard models.

Contribution

It introduces a systematic study of fidelity susceptibility in Hubbard models, highlighting its sensitivity and utility in identifying multiple phase transitions and crossovers.

Findings

Fidelity susceptibility is highly sensitive to state changes.

It can detect Mott transitions, spin transitions, and Fermi-liquid crossovers.

The method is computationally inexpensive.

Abstract

A generalized version of the fidelity susceptibility of single-band and multi-orbital Hubbard models is systematically studied using single-site dynamical mean-field theory in combination with a hybridization expansion continuous-time quantum Monte Carlo impurity solver. We find that the fidelity susceptibility is extremely sensitive to changes in the state of the system. It can be used as a numerically inexpensive tool to detect and characterize a broad range of phase transitions and crossovers in Hubbard models, including (orbital-selective) Mott metal-insulator transitions, high-spin to low-spin transitions, Fermi-liquid to non-Fermi-liquid crossovers, and spin-freezing crossovers.