Sound Propagation and Transport Properties of Liquid $^3$He in Aerogel

TL;DR

This paper investigates how superfluid helium-3 behaves when confined in aerogel, focusing on transport properties and sound propagation to understand quasiparticle scattering and superfluid interactions.

Contribution

It provides experimental and theoretical analysis of sound propagation and transport in superfluid helium-3 within aerogel, testing models of quasiparticle scattering in a short mean free path regime.

Findings

Sound and transport properties are sensitive to aerogel-induced scattering.

Theoretical models align with experimental data on quasiparticle interactions.

Insights into superfluid-aerogel interactions are gained.

Abstract

Superfluid $^3$He confined in aerogel offers a unique chance to study the effects of a short mean free path on the properties of a well defined superfluid Fermi liquid with anisotropic pairing. Transport coefficients and collective excitations, e.g. longitudinal sound, are expected to react sensitively to a short mean free path and to offer the possibility for testing recently developed models for quasiparticle scattering at aerogel strands. Sound experiments, together with a theoretical analysis based on Fermi liquid theory for systems with short mean free paths, should give valuable insights into the interaction between superfluid $^3$He and aerogel.