Ring exchanges and the supersolid phase of 4He

TL;DR

This study uses Path Integral Monte Carlo to analyze ring exchange processes in bulk helium-4, concluding that perfect crystals are unlikely to exhibit supersolid behavior due to exchange frequency scaling.

Contribution

It provides a quantitative analysis of exchange frequencies in helium-4 and assesses their role in supersolidity, a novel application of lattice modeling to this problem.

Findings

Superfluid behavior is unlikely in perfect 4He crystals.

Exchange frequencies scale in a way that suppresses supersolidity.

The lattice model fits exchange data effectively.

Abstract

Using Path Integral Monte Carlo we calculate exchange frequencies in bulk hcp 4He as atoms undergo ring exchange. We fit the frequencies to a lattice model and examine whether such atoms could become a supersolid, that is have a non-classical rotational inertia. We find that the scaling with respect to the number of exchanging atoms is such that superfluid behavior will not be observed in a perfect 4He crystal.