arXiv:2109.03714 · Physical Review A
Quantum quench thermodynamics at high temperatures
Adalberto D. Varizi, Raphael C. Drumond, Gabriel Teixeira Landi
Abstract
The entropy produced when a system undergoes an infinitesimal quench is directly linked to the work parameter susceptibility, making it sensitive to the existence of a quantum critical point. Its singular behavior at $T=0$, however, disappears as the temperature is raised, hindering its use as a tool for spotting quantum phase transitions. Notwithstanding, the entropy production can be split into classical and quantum components, related with changes in populations and coherences. In this paper we show that these individual contributions can continue to exhibit signatures of the quantum phase transition, even at arbitrarily high temperatures. This is a consequence of their intrinsic connection to the derivatives of the energy eigenvalues and the energy eigenbasis. We illustrate our results in the Landau-Zener model and the prototypical quantum critical system, the $XY$ model.