Anomalous Heat and Momentum Transport Arising from Surface Roughness in a Normal $^3$He Slab

TL;DR

This paper investigates how surface roughness in a mesoscopic $^3$He film causes anomalous heat and momentum transport, with calculations linking these effects to surface properties and film thickness.

Contribution

It introduces a theoretical framework for understanding anomalous transport in $^3$He films caused by surface roughness and provides explicit formulas for thermal conductivity and viscosity.

Findings

Surface roughness induces coherent mixed scattering channels.

Thermal conductivity and viscosity depend on film thickness and surface autocorrelation.

The model helps isolate effects of confinement and surface roughness.

Abstract

I discuss heat and momentum transport in a mesoscopic film of $^3$He, confined by rough walls in the normal Fermi liquid state. Inelastic binary quasiparticle scattering mediated by elastic scattering from the surface roughness gives rise to a coherent "mixed"scattering channel that drives anomalous transport over a range of temperature. I calculate the thermal conductivity and viscosity of the film in this regime and derive these in terms of the film thickness and autocorrelation function of the surface roughness, which enters the formulation as an independent input. This calculation can be useful in understanding and isolating the effects of confinement and surface roughness, especially in the context of exploring the superfluid state in the film.