Vortex core contribution to textural energy in 3He-B below 0.4Tc

TL;DR

This paper investigates how vortex cores influence the energy landscape in superfluid 3He-B at temperatures below 0.4Tc, revealing a transition from symmetric to broken-symmetry cores and extending measurements to lower temperatures.

Contribution

It extends previous measurements of vortex core contributions to superfluid 3He-B below 0.2Tc and explores potential new core transitions at lower temperatures.

Findings

Identified a step-like change in core contribution at 0.6Tc indicating a core symmetry transition.

Extended measurements of core energy contributions below 0.2Tc.

Searched for, but did not confirm, a new lower-symmetry core transition.

Abstract

Vortex lines affect the spatial order-parameter distribution in superfluid 3He-B owing to superflow circulating around vortex cores and due to the interaction of the order parameter in the core and in the bulk as a result of superfluid coherence over the whole volume. The step-like change of the latter contribution at 0.6Tc (at a pressure of 29bar) signifies the transition from axisymmetric cores at higher temperatures to broken-symmetry cores at lower temperatures. We extended earlier measurements of the core contribution to temperatures below 0.2Tc, in particular searching for a possible new core transition to lower symmetries. As a measuring tool we track the energy levels of magnon condensate states in a trap formed by the order-parameter texture.