Stability of vortex lines in liquid 3He-4He mixtures at zero temperature

TL;DR

This paper investigates the stability of vortex lines in liquid helium mixtures at zero temperature, identifying conditions under which vortices with 3He-rich cores are stable or become unstable, using a density functional approach.

Contribution

It provides a detailed analysis of vortex stability in helium mixtures at zero temperature, highlighting the pressure-concentration conditions for instability.

Findings

Stable vortices exist below 6.6% 3He concentration.

Vortices become metastable or unstable under supersaturation or tensile stress.

The pressure-concentration curve for vortex instability is determined.

Abstract

At low temperatures and 3He concentrations below 6.6 %, there is experimental evidence about the existence in liquid helium mixtures, of stable vortices with 3He-rich cores. When the system is either supersaturated or submitted to a tensile strength, vortices lose stability becoming metastable and eventually completely unstable, so that their cores freely expand. Within a density functional approach, we have determined the pressure-3He concentration curve along which this instability appears at zero temperature.