Observation of half-quantum vortices in topological superfluid 3He

TL;DR

This paper reports the first observation of half-quantum vortices in the polar phase of superfluid 3He, opening new avenues for studying Majorana modes in topological quantum matter.

Contribution

It provides experimental evidence of HQVs in superfluid 3He polar phase, previously only predicted, enabling future research on Majorana modes.

Findings

Half-quantum vortices observed in superfluid 3He polar phase

Vortices created via rotation or Kibble-Zurek mechanism

NMR signatures used for vortex identification

Abstract

One of the most sought-after objects in topological quantum matter systems is a vortex carrying half a quantum of circulation. They were originally predicted to exist in superfluid 3He-A, but have never been resolved there. Here we report an observation of half-quantum vortices (HQVs) in the polar phase of superfluid 3He. The vortices are created with rotation or by the Kibble-Zurek mechanism and identified based on their nuclear magnetic resonance signature. This discovery provides a pathway for studies of unpaired Majorana modes bound to the HQV cores in the polar-distorted A phase.