Topological Josephson heat engine

Benedikt Scharf,Francesco Giazotto,Ewelina M Hankiewicz,Elia Strambini,Alessandro Braggio

doi:10.1038/s42005-020-00463-6

Benedikt Scharf, Francesco Giazotto + Show 3 more

Open Access

https://doi.org/10.1038/s42005-020-00463-6

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Abstract

Topological superconductors represent a fruitful playing ground for fundamental research as well as for potential applications in fault-tolerant quantum computing. Especially Josephson junctions based on topological superconductors remain intensely studied, both theoretically and experimentally. The characteristic property of these junctions is their 4π-periodic ground-state fermion parity in the superconducting phase difference. Using such topological Josephson junctions, we introduce the concept of a topological Josephson heat engine. We discuss how this engine can be implemented as a Josephson–Stirling cycle in topological superconductors, thereby illustrating the potential of the intriguing and fruitful marriage between topology and coherent thermodynamics. It is shown that the Josephson–Stirling cycle constitutes a highly versatile thermodynamic machine with different modes of operation controlled by the cycle temperatures. Finally, the thermodynamic cycle reflects the hallmark 4π-periodicity of topological Josephson junctions and could therefore be envisioned as a complementary approach to test topological superconductivity.

Highlights

Topological superconductors represent a fruitful playing ground for fundamental research as well as for potential applications in fault-tolerant quantum computing
We propose a topological Josephson heat engine implemented by a Josephson–Stirling cycle and discuss its thermodynamic[17,18,19,20,21,22,23] properties
Using a Josephson junction based on a quantum spin Hall (QSH) insulator as an example, we show how topological Josephson junctions represent versatile thermodynamic machines with various operating modes

Summary

Introduction

Topological superconductors represent a fruitful playing ground for fundamental research as well as for potential applications in fault-tolerant quantum computing. Their topological nature is reflected in a ground-state fermion parity that is 4π-periodic in the superconducting phase difference φ. We propose a topological Josephson heat engine implemented by a Josephson–Stirling cycle and discuss its thermodynamic[17,18,19,20,21,22,23] properties. The thermodynamic cycle properties reflect the 4πperiodicity of the topological ground state, distinguishing between parity-conserving and non-parity-conserving engines.

Results

Conclusion