Thermal History of Solid 4He Under Oscillation

TL;DR

This study investigates the thermal history of solid 4He under oscillation, revealing multivalued frequency shifts at low temperatures linked to vortex dynamics and dislocation responses, providing insights into quantum and defect behaviors.

Contribution

It presents new experimental observations of multivalued frequency shifts in solid 4He, connecting vortex pinning and dislocation effects to the thermal history under oscillation.

Findings

Frequency shift below 100 mK is multivalued and depends on preparation.

Vortex motion and pinning explain the observed phenomena.

Dislocation lines respond to oscillating stress fields.

Abstract

We have studied the thermal history of the resonant frequency of a torsional oscillator containing solid 4He. We find that the magnitude of the frequency shift that occurs below 100 mK is multivalued in the low temperature limit, with the exact value depending on how the state is prepared. This result can be qualitatively explained in terms of the motion and pinning of quantized vortices within the sample. Several aspects of the data are also consistent with the response of dislocation lines to oscillating stress fields imposed on the solid.