Relaxation of superflow in a network: an application to the dislocation model of supersolidity of helium crystals

TL;DR

This paper investigates how superfluid flow relaxes in a dislocation network within helium-4 crystals, revealing a crossover to a quasi-superfluid state at temperatures below the superfluid transition, with decay times increasing exponentially as temperature decreases.

Contribution

It introduces a model for superflow relaxation in dislocation networks, highlighting a temperature-independent crossover to a quasi-superfluid state in helium-4 crystals.

Findings

Crossover into a quasi-superfluid state occurs between T_c and T_d.

Decay time of flow increases exponentially below the crossover temperature.

Crossover temperature is independent of dislocation density.

Abstract

We have considered the dislocation network model for the supersolid state in He-4 crystals. In difference with uniform 2D and 3D systems, the temperature of superfluid transition T_c in the network is much smaller than the degeneracy temperature T_d. It is shown that a crossover into a quasi superfluid state occurs in the temperature interval between T_c and T_d. Below the crossover temperature the time of decay of the flow increases exponentially under decrease of the temperature. The crossover has a continuous character and the crossover temperature does not depend on the density of dislocations.