Dissipation peak as an indicator of sample inhomogeneity in solid $^4$He oscillator experiments

TL;DR

This paper presents a phenomenological model linking dissipation peaks to sample inhomogeneity in solid helium-4 oscillator experiments, revealing that many observed peaks are broadened due to inhomogeneity rather than intrinsic effects.

Contribution

The paper introduces a simple model that relates dissipation peaks to sample uniformity, providing a new method to assess inhomogeneity in solid helium experiments.

Findings

Many dissipation peaks are inhomogeneously broadened.

Homogeneous samples follow a specific frequency-damping relation.

Inhomogeneity affects interpretation of supersolid signals.

Abstract

A simple phenomenological model is developed for the recent torsional oscillator experiments on solid $^4$He. Within this model, for a homogeneous sample there is a specific quantitative relation between the change in the oscillator's frequency and its maximum damping at the apparent supersolid transition. Much of the published data do not satisfy this relation, indicating that the dissipation peaks in those samples are strongly inhomogeneously broadened.