Coherent diffraction of thermal currents in Josephson tunnel junctions

TL;DR

This paper theoretically explores how magnetic fields influence heat flow in Josephson tunnel junctions, revealing phase-dependent diffraction effects similar to those seen in electrical currents, and proposes an experiment to observe these phenomena.

Contribution

It introduces a theoretical framework for phase-dependent thermal diffraction in Josephson junctions and analyzes different geometries, proposing an experimental setup for detection.

Findings

Thermal heat flux exhibits coherent diffraction patterns under magnetic fields.

Phase differences can undergo -slips affecting thermal transport.

Different junction geometries show distinct thermal diffraction behaviors.

Abstract

We theoretically investigate heat transport in temperature-biased Josephson tunnel junctions in the presence of an in-plane magnetic field. In full analogy with the Josephson critical current, the phase-dependent component of the heat flux through the junction displays coherent diffraction. Thermal transport is analyzed in three prototypical junction geometries highlighting their main differences. Notably, minimization of the Josephson coupling energy requires the quantum phase difference across the junction to undergo \pi-slips in suitable intervals of magnetic flux. An experimental setup suited to detect thermal diffraction is proposed and analyzed.