Quantum correlations and thermodynamic performances of two-qubit engines with local and collective baths

TL;DR

This paper studies two-qubit quantum heat engines operating in non-equilibrium environments, revealing how quantum correlations like discord and entanglement influence their thermodynamic performance.

Contribution

It introduces a generalized Otto cycle with coupled qubits interacting with local and collective baths, exploring the role of quantum correlations in engine efficiency.

Findings

Quantum engines show work dependence on quantum discord and entanglement.

Non-equilibrium common environments can enhance engine performance.

Quantum correlations are linked to thermodynamic outputs.

Abstract

We investigate heat engines whose working substance is made of two coupled qubits performing a generalised Otto cycle by varying their applied magnetic field or their interaction strength during the compression and expansion strokes. During the heating and cooling strokes, the two qubits are coupled to local and common environments that are not necessarily at equilibrium. We find instances of quantum engines coupled to non equilibrium common environments exhibiting non-trivial connections to quantum correlations as witnessed by a monotonic dependence of the work produced on quantum discord and entanglement.