A Gross-Pitaevskii Treatment for Supersolid He

TL;DR

This paper proposes a Gross-Pitaevskii superfluid model of vacancies to explain non-linear rotational susceptibility in solid helium, suggesting all pure Bose solids may inherently be supersolid.

Contribution

It introduces a Gross-Pitaevskii framework for supersolid helium and discusses how crystal imperfections influence the observed phenomena.

Findings

Vacancy superfluidity can explain NCRI in solid helium

Density enhancements due to imperfections impact observations

Ground state of pure Bose solids likely supersolid

Abstract

The observations of non-linear rotational susceptibility (NCRI) in samples of solid He below 1-200 mK temperatures are conjectured to be describable in terms of a rarified Gross-Pitaevskii superfluid of vacancies (or, more generally, incommensuracies) with a transition temperature of about 50 mK, whose density is locally enhanced by crystal imperfections. We argue that the observations can be much affected by this density enhancement. We argue also that it is likely that the ground state of every pure Bose solid is supersolid.