Quantum Chernoff Bound metric for the XY model at finite temperature

TL;DR

This paper uses the Quantum Chernoff Bound metric to analyze the finite temperature phase diagram of the XY spin chain, revealing quantum-critical and quasi-classical regions through information-theoretic measures.

Contribution

It demonstrates that the Quantum Chernoff Bound metric effectively characterizes phase transitions in the XY model at finite temperature, extending previous Bures metric analyses.

Findings

Quantum Chernoff Bound metric identifies quantum-critical regions.

Different information-theoretic distances reveal similar phase diagram features.

The approach extends understanding of finite-temperature quantum phase transitions.

Abstract

We explore the finite temperature phase diagram of the anisotropic XY spin chain using the Quantum Chernoff Bound metric on thermal states. The analysis of the metric elements allows to easily identify, in terms of different scaling with temperature, quasi-classical and quantum-critical regions. These results extend recent ones obtained using the Bures metric and show that different information-theoretic notions of distance can carry the same sophisticated information about the phase diagram of an interacting many-body system featuring quantum-critical points.