Vortices observed and to be observed

TL;DR

This paper reviews various types of vortices in unconventional superfluids and superconductors, highlighting their observed and potential forms, properties, and associated quasiparticles, emphasizing their topological and quantum characteristics.

Contribution

It provides a comprehensive overview of unconventional vortices, including new types like half-quantum vortices and vortex sheets, and discusses their properties and significance.

Findings

Observation of continuous singly and doubly quantized vortices in 3He-A

Discussion of half-quantum vortices (Alice strings) in superfluids

Analysis of vortex properties related to fermionic quasiparticles

Abstract

Linear defects are generic in continuous media. In quantum systems they appear as topological line defects which are associated with a circulating persistent current. In relativistic quantum vacuum they are known as cosmic strings, in superconductors as quantized flux lines, and in superfluids and low-density atomic Bose-Einstein condensates as quantized vortex lines. We discuss unconventional vortices in unconventional superfluids and superconductors, which have been observed or have to be observed, such as continuous singly and doubly quantized vortices in 3He-A and chiral Bose condensates; half-quantum vortices (Alice strings) in 3He-A and in nonchiral Bose condensates; Abrikosov vortices with fractional magnetic flux in chiral and d-wave superconductors; vortex sheets in 3He-A and chiral superconductors; the nexus -- combined object formed by vortices and monopoles. Some properties of vortices related to fermionic quasiparticles living in the vortex core are also discussed.