Classical stability of supercurrent in one dimension: a numerical study

TL;DR

This paper investigates the classical and quantum mechanisms of supercurrent decay in one-dimensional superfluids, highlighting the conditions under which classical relaxation occurs and identifying critical droplets that facilitate decay.

Contribution

It provides a numerical analysis of classical phase slips and identifies conditions where classical decay is possible, extending understanding of supercurrent stability in 1D superfluids.

Findings

Classical relaxation rate vanishes in the uniform limit.

Quantum relaxation via phonons dominates in the uniform system.

Smooth periodic potentials enable classical decay through critical droplets.

Abstract

We report results of a classical simulation of thermal phase slips, and the associated relaxation of supercurrent, in a ring-shaped one-dimensional superfluid. We find that the classical relaxation rate vanishes in the uniform limit. This leaves the quantum relaxation, with momentum transfer to phonons, the only mechanism of supercurrent decay in the uniform system. In the presence of a smooth periodic potential, classical decay becomes possible, and we identify a family of moving critical droplets that can mediate it.