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Quantum Otto engine powered by critical XY-$\Gamma$ chain

by Anass Hminat, Abdallah Slaoui, Rachid Ahl Laamara, and Amine Jaouadi

Submission summary

Authors (as registered SciPost users):

Amine Jaouadi · Abdallah Slaoui

Abstract

We present a theoretical study of the thermodynamic properties of a four-stroke engine whose working medium is an \(XY\) quantum spin chain. The cycle alternates unitary strokes—realized via controlled modulations of a transverse magnetic field—with thermalization strokes produced by coupling the chain to thermal reservoirs at different temperatures. The open-system dynamics are treated within a thermodynamically consistent formalism based on a nonlocal Lindblad master equation. Depending on the choice of system parameters, the device exhibits four distinct operating regimes and can act either as a heat engine or as a refrigerator. Notably, we observe a marked improvement of the machine’s performance in the vicinity of the quantum critical point. We also analyze the roles played by the off-diagonal coupling \(\Gamma\) and the anisotropy parameter \(\gamma\), and discuss strategies to optimize the engine’s figures of merit in both operational modes.

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• Provide a novel and synergetic link between different research areas.
• Open a new pathway in an existing or a new research direction, with clear potential for multi-pronged follow-up work
• Detail a groundbreaking theoretical/experimental/computational discovery
• Present a breakthrough on a previously-identified and long-standing research stumbling block