Phase-tunable Josephson thermal router

TL;DR

This paper reports the experimental development of a phase-tunable Josephson thermal router that can control heat flow between two different temperature reservoirs, advancing the field of quantum caloritronics and thermal logic devices.

Contribution

It introduces the first multi-terminal Josephson-based thermal router capable of modulating heat transfer via phase control, enabling complex heat management in quantum systems.

Findings

Successfully demonstrated heat flow control between two terminals

Achieved thermal gradient inversion through phase tuning

Paved the way for thermal logic components in quantum devices

Abstract

Since the the first studies of thermodynamics, heat transport has been a crucial element for the understanding of any thermal system. Quantum mechanics has introduced new appealing ingredients for the manipulation of heat currents, such as the long-range coherence of the superconducting condensate. The latter has been exploited by phase-coherent caloritronics, a young field of nanoscience, to realize Josephson heat interferometers, which can control electronic thermal currents as a function of the external magnetic flux. So far, only one output temperature has been modulated, while multi-terminal devices that allow to distribute the heat flux among different reservoirs are still missing. Here, we report the experimental realization of a phase-tunable thermal router able to control the heat transferred between two terminals residing at different temperatures. Thanks to the Josephson effect, our structure allows to regulate the thermal gradient between the output electrodes until reaching its inversion. Together with interferometers, heat diodes and thermal memories, the thermal router represents a fundamental step towards the thermal conversion of non-linear electronic devices, and the realization of caloritronic logic components.