The Vortex Lability In a Supersaturated Superfluid ³ He-⁴ He Mixture and the Quantum Phase-Separation Kinetics

Abstract

The supersaturated superfluid ³ He-⁴ He mixture in the presence of quantized vortices is considered. A specific type of the lability against the vortex core expansion arises from concentrating ³ He atoms onto the vortex core. This affects significantly the region of the ³ He concentrations at which the rate of nucleating stable ³ He-concentrated phase can be noticeable. The most clear case of the vortex structure is a straight-line vortex with the uniformly distributed 3He atoms along the core. Such lability leads to some features in the thermal activation and quantum tunneling nucleation, resulting, in particular, in a relatively small supersaturation of about 1% which can be achieved. The critical value of the supersaturations corresponding to the vortex lability is dispersed because of the finite size of the ³ He-concentrated phase along the vortex core. We analyze this dispersion and its effect on the quantum separation in supersaturated ³ He-⁴ He mixtures. The value of the supersaturation conserves its order of the magnitude, changing only by a numerical factor. We also emphasize an important difference of the coefficient in the term responsible for the lability from the superfluid density ρs. The supersaturation observed in experiments lies within the range of the vortex lability and, probably, is connected with this lability.