Quantum unital Otto heat engines: using Kirkwood-Dirac quasi-probability for the engine's coherence to stay alive

• URL: http://arxiv.org/abs/2405.04243v2
• Date: Sun, 27 Apr 2025 21:18:21 GMT
• Title: Quantum unital Otto heat engines: using Kirkwood-Dirac quasi-probability for the engine's coherence to stay alive
• Authors: Abdelkader El Makouri, Abdallah Slaoui, Rachid Ahl Laamara,
• Abstract summary: We show how to compute the cumulants of either the dephased or undephased heat engine.<n>For a qubit, we give the analytical expressions of the averages and variances for arbitrary unitaries and unital channels.<n>We show that non-adiabatic transitions are not always detrimental to thermodynamic quantities.
• Score: 0.0
• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: In this work, we consider quantum unital Otto heat engines. The latter refers to the fact that both the unitaries of the adiabatic strokes and the source of the heat provided to the engine preserve the maximally mixed state. We show how to compute the cumulants of either the dephased or undephased engine. For a qubit, we give the analytical expressions of the averages and variances for arbitrary unitaries and unital channels. We do a detailed comparative study between the dephased and undephased heat engines. More precisely, we focus on the effect of the parameters on the average work and its reliability and efficiency. As a case study of unital channels, we consider a quantum projective measurement. We show on which basis we should projectively measure the qubit, either the dephased or undephased heat engine, to extract higher amounts of work, increase the latter's reliability, and increase efficiency. Further, we show that non-adiabatic transitions are not always detrimental to thermodynamic quantities. Our results, we believe, are important for heat engines fueled by quantum measurement.

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