https://doi.org/10.1140/epjb/s10051-026-01201-7
Research - Condensed Matter
Quantum Stirling heat machine using two coupled superconducting charge qubits
Laboratory of Mechanics and High Energy Physics, Department of Physics, Faculty of Sciences Aïn Chock, University Hassan II, P.O. Box 5366, Maarif, 20100, Casablanca, Morocco
a
This email address is being protected from spambots. You need JavaScript enabled to view it.
Received:
1
April
2026
Accepted:
6
June
2026
Published online:
3
July
2026
Abstract
In this paper, we introduce a quantum thermal machine based on the Stirling cycle and explore its operation in distinct modes: the accelerator, the refrigerator, the heater, and the quantum heat engine (QHE). The working material under investigation consists of two capacitively coupled superconducting charge (SC) qubits. We examine how the coupling energy, the Josephson energies, and the equilibrium temperatures affect the efficiency and coefficient of performance (COP) of the Stirling heat engine and the Stirling refrigerator. The results indicate that, by adjusting the system parameters, the Stirling cycle can operate either as a QHE or as a quantum refrigerator, achieving notable efficiency and a high coefficient of performance. In particular, when the mutual coupling energy of the cold reservoir is significantly lower than that of the hot reservoir, the system functions as a QHE with optimal efficiency. However, reversing this condition enables the system to function as a quantum refrigerator with an optimal coefficient of performance.
Copyright comment Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
© The Author(s), under exclusive licence to EDP Sciences, SIF and Springer-Verlag GmbH Germany, part of Springer Nature 2026
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
