Work statistics and thermal phase transitions

TL;DR

This paper reveals that the average work done in quantum many-body models shows nonanalytic behavior at finite temperatures, serving as a signature of thermal phase transitions, contrary to the common belief that such singularities vanish at higher temperatures.

Contribution

It demonstrates that work statistics can indicate thermal phase transitions at finite temperatures in models like the Dicke and Lipkin-Meshkov-Glick models, challenging previous assumptions.

Findings

Nonanalytic behavior of average work at finite temperature.

Work statistics signal thermal phase transitions.

Contradicts the belief that singularities vanish at higher temperatures.

Abstract

Many previous studies have demonstrated that work statistics can exhibit certain singular behaviors in the quantum critical regimes of many-body systems at zero or very low temperatures. However, as the temperature increases, it is commonly believed that such singularities will vanish. Contrary to this common recognition, we report a nonanalytic behavior of the averaged work done, which occurs at finite temperature, in the Dicke model as well as the Lipkin-Meshkov-Glick model subjected to the sudden quenches of their work parameters. It is revealed that work statistics can be viewed as a signature of the thermal phase transition when the quenched parameters are tuned across the critical line that separates two different thermal phases.