Annealing of supersolidity in plastically deformed solid $^4$He

TL;DR

This study models how supersolidity in solid helium-4 emerges temporarily during plastic deformation and disappears upon annealing, with residual effects remaining at lower temperatures due to dislocation dynamics.

Contribution

It introduces a coupled continuum plasticity and Ginzburg-Landau model to explain supersolidity phenomena in solid helium-4.

Findings

Supersolidity appears as a transient during plastic deformation at higher temperatures.

Annealing leads to the disappearance of supersolidity.

Residual supersolidity persists at low temperatures due to arrested dislocation climb.

Abstract

We present a numerical study of a continuum plasticity field coupled to a Ginzburg-Landau model for superfluidity. The results suggest that a supersolid fraction may appear as a long-lived transient during the time evolution of the plasticity field at higher temperatures where both dislocation climb and glide are allowed. Supersolidity, however, vanishes with annealing. As the temperature is decreased, dislocation climb is arrested and any residual supersolidity due to incomplete annealing remains frozen. Our results provide a resolution of many perplexing issues concerning a variety of experiments on solid $^4$He.