The glassy response of double torsion oscillators in solid Helium-4

TL;DR

This paper proposes a glassy subsystem model to explain mechanical anomalies in solid Helium-4 observed via torsion oscillators, negating the need for a supersolid interpretation and unifying different experimental results.

Contribution

It introduces a glassy back-action model that explains frequency shifts and dissipation in both single and double torsion oscillator experiments with solid Helium-4.

Findings

Glassy back-action accounts for observed frequency changes.

Dissipation peaks are explained by glassy dynamics.

Model applies to multiple oscillator modes.

Abstract

Single and double torsion oscillators have been used successfully to measure the anomalous change in resonant frequency and accompanying dissipation in solid He-4. We present a glass description of the mechanical anomalies found in torsion oscillator measurements. Our results show that it is not necessary to invoke a supersolid interpretation to explain these mechanical anomalies. Previously, we demonstrated that the back-action of a glassy subsystem present in solid He-4 can account for frequency change and dissipation peak in many single torsion oscillator experiments. Here, we show that the same glassy back-action can explain the experimental results of the composite torsion oscillator developed by the Rutgers group, which measures the response of solid He-4 at the in-phase mode f1=496 Hz and out-of-phase mode f2=1173 Hz.