On the Possibility of "Dry" Friction in Superfluid He-4

TL;DR

This paper explores the potential for 'dry' friction in superfluid helium-4, proposing a microscopic explanation for the loss of superfluid density at certain temperatures and predicting friction effects related to roton energies.

Contribution

It introduces a novel microscopic model explaining superfluid density exhaustion and predicts 'dry' friction phenomena in helium-II at low temperatures.

Findings

Superfluid density decreases at T > 0.5-1 K due to wall effects.

Potential well formation for 3D-rotons near the wall.

Possibility of 'dry' friction in helium-II at T < T_c.

Abstract

We propose a possible microscopic explanation of the exhaustion of \rho_s of helium-II on the wall at T>T_{c} = 0.5 - 1 K and predict a possibility of the existence in He-II of the "dry" friction at T < T_{c}. Both of the effects connect with that the energy of the 2D-rotons is 2K less then the energy of 3D-rotons, so the wall is a potential well for the last ones.