Surface Waves on Superfluid 3He and 4He

TL;DR

This study investigates surface waves on superfluid helium-3 and helium-4 at near-zero temperatures, providing extensive experimental data that challenges existing theoretical models of inviscid superfluid surface dynamics.

Contribution

It presents one of the first detailed experimental analyses of surface waves on superfluid 3He and offers comprehensive data on 4He for comparison with theoretical predictions.

Findings

Dozens of surface wave resonances observed

Up to 11 overtones detected

Discrepancies between data and models

Abstract

Surface waves on both superfluid 3He and 4He were examined with the premise, that these inviscid media would represent ideal realizations for this fluid dynamics problem. The work on 3He is one of the first of its kind, but on 4He it was possible to produce much more complete set of data for meaningful comparison with theoretical models. Most measurements were performed at the zero temperature limit, meaning T < 100 mK for 4He and T ~ 100 {\mu}K for 3He. Dozens of surface wave resonances, including up to 11 overtones, were observed and monitored as the liquid depth in the cell was varied. Despite of the wealth of data, perfect agreement with the constructed theoretical models could not be achieved.