Absorption of heat into a superconductor-normal metal-superconductor junction from a fluctuating environment

TL;DR

This paper investigates how electromagnetic fluctuations from an environment can transfer heat to a superconductor-normal metal-superconductor junction, altering its supercurrent and potentially increasing its critical current.

Contribution

It introduces a model for heat absorption from environmental fluctuations in a diffusive SNS junction, revealing effects on supercurrent and critical current.

Findings

Environmental fluctuations can increase the junction's critical current.

Heat transfer induces qualitative changes in the current-phase relation.

The effects are expected in other conducting weak links.

Abstract

We study a diffusive superconductor-normal metal-superconductor junction in an environment with intrinsic incoherent fluctuations which couple to the junction through an electromagnetic field. When the temperature of the junction differs from that of the environment, this coupling leads to an energy transfer between the two systems, taking the junction out of equilibrium. We describe this effect in the linear response regime and show that the change in the supercurrent induced by this coupling leads to qualitative changes in the current-phase relation and for a certain range of parameters, an increase in the critical current of the junction. Besides normal metals, similar effects can be expected also in other conducting weak links.