Heat transport through a Josephson junction

TL;DR

This paper analyzes heat transport in Josephson tunnel junctions, deriving formulas for cooling power, heat current noise, and full counting statistics, considering different bias conditions and quantum fluctuations, with implications for sensitive detection.

Contribution

It introduces a comprehensive theoretical framework for heat transport in Josephson junctions, including time-dependent phase effects and quantum fluctuations, expanding understanding of their thermal properties.

Findings

Derived general formula for cooling power under arbitrary phase dynamics

Calculated heat current noise and full counting statistics

Identified regimes suitable for low-power, sensitive detection

Abstract

We discuss heat transport through a Josephson tunnel junction under various bias conditions. We first derive the formula for the cooling power of the junction valid for arbitrary time dependence of the Josephson phase. Combining it with the classical equation of motion for the phase, we find the time averaged cooling power as a function of bias current or bias voltage. We also find the noise of the heat current and, more generally, the full counting statistics of the heat transport through the junction. We separately consider the metastable superconducting branch of the current-voltage characteristics allowing quantum fluctuations of the phase in this case. This regime is experimentally attractive since the junction has low power dissipation, low impedance and therefore may be used as a sensitive detector.