Optimal work extraction and thermodynamics of quantum measurements and correlations

TL;DR

This paper investigates how quantum and classical correlations influence work extraction in quantum systems, revealing optimal protocols and the thermodynamic tradeoffs involved, especially highlighting the role of quantum discord.

Contribution

It introduces optimal, state-dependent protocols for extracting work from quantum and classical correlations, emphasizing the necessity of system-ancilla interaction for quantum discord.

Findings

Classical correlations can be fully exploited locally for work extraction.

Quantum discord requires specific system-ancilla interactions to harness work.

The work content depends on the type of correlations and measurement backaction.

Abstract

We analyze the role of indirect quantum measurements in work extraction from quantum systems in nonequilibrium states. In particular, we focus on the work that can be obtained by exploiting the correlations shared between the system of interest and an additional ancilla, where measurement backaction introduces a nontrivial thermodynamic tradeoff. We present optimal state-dependent protocols for extracting work from both classical and quantum correlations, the latter being measured by discord. We show that, while the work content of classical correlations can be fully extracted by performing local operations on the system of interest, the amount of work related to quantum discord requires a specific driving protocol that includes interaction between system and ancilla.