Fidelity approach to the disordered quantum XY model

TL;DR

This paper investigates the disordered quantum XY model using ground state fidelity susceptibility, revealing phase diagram features such as the Ising critical line and Griffiths phases through numerical analysis.

Contribution

It introduces a fidelity-based numerical method to identify phase boundaries and Griffiths phases in the disordered quantum XY model.

Findings

Fidelity susceptibility accurately detects phase transitions.

Scaling properties reveal critical lines and Griffiths phases.

Results agree with previous analytical and numerical studies.

Abstract

We study the random XY spin chain in a transverse field by analyzing the susceptibility of the ground state fidelity, numerically evaluated through a standard mapping of the model onto quasi-free fermions. It is found that the fidelity susceptibility and its scaling properties provide useful information about the phase diagram. In particular it is possible to determine the Ising critical line and the Griffiths phase regions, in agreement with previous analytical and numerical results.