Thermally Driven Josephson Oscillations in Superfluid 4He

TL;DR

This paper demonstrates that a temperature differential can induce superfluid oscillations in helium-4, confirming the general Josephson frequency relation through experiments near the superfluid transition temperature.

Contribution

It provides experimental validation of the Josephson frequency relation in superfluid helium driven by thermal gradients.

Findings

Temperature differential drives superfluid oscillations.

Measured oscillation frequency matches Josephson relation.

Oscillations observed near the superfluid transition temperature.

Abstract

We find that a temperature differential can drive superfluid oscillations in 4He. The oscillations are excited by a heater which causes a time dependent temperature differential across an array of 70nm apertures. By measuring the oscillation frequency and simultaneously determining both temperature and pressure differentials we prove the validity of the most general form of the Josephson frequency relation. These observations were made near saturated vapor pressure, within a few mK of the superfluid transition temperature.