Thermodynamics of a phase-driven proximity Josephson junction

TL;DR

This paper explores the thermodynamic behavior of a superconductor/normal metal/superconductor Josephson junction, analyzing phase-driven processes and cycles like Otto and Stirling for potential energy applications.

Contribution

It introduces a thermodynamic framework for Josephson junctions, linking phase difference, supercurrent, temperature, and entropy through equations of state.

Findings

Derived equations of state for the junction's thermodynamic variables.

Characterized quasi-static processes involving heat and work exchange.

Analyzed the performance of Josephson-based Otto and Stirling cycles in engine and refrigerator modes.

Abstract

We study the thermodynamic properties of a superconductor/normal metal/superconductor Josephson junction {in the short limit}. Owing to the proximity effect, such a junction constitutes a thermodynamic system where {phase difference}, supercurrent, temperature and entropy are thermodynamical variables connected by equations of state. These allow conceiving quasi-static processes that we characterize in terms of heat and work exchanged. Finally, we combine such processes to construct a Josephson-based Otto and Stirling cycles. We study the related performance in both engine and refrigerator operating mode.