Work and Quantum Phase Transitions: Is there Quantum Latency?

TL;DR

This paper explores quantum phase transitions through non-equilibrium thermodynamics, introducing the concept of quantum latent work for first order transitions and relating irreversible work to fidelity susceptibility for second order transitions.

Contribution

It introduces the concept of quantum latent work for first order quantum phase transitions and links irreversible work to fidelity susceptibility in second order transitions.

Findings

Discontinuous average work in first order transitions

Quantum latent work analogous to classical latent heat

Irreversible work related to fidelity susceptibility in second order transitions

Abstract

We study the physics of quantum phase transitions from the perspective of non-equilibrium thermodynamics. For first order quantum phase transitions, we find that the average work done per quench in crossing the critical point is discontinuous. This leads us to introduce the quantum latent work in analogy with the classical latent heat of first order classical phase transitions. For second order quantum phase transitions the irreversible work is closely related to the fidelity susceptibility for weak sudden quenches of the system Hamiltonian. We demonstrate our ideas with numerical simulations of first, second, and infinite order phase transitions in various spin chain models.