Vortex-bound solitons in topological superfluid 3He

Loading...
Thumbnail Image

Access rights

openAccess

URL

Journal Title

Journal ISSN

Volume Title

A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä

Date

2023-06-02

Major/Subject

Mcode

Degree programme

Language

en

Pages

27
1-27

Series

Journal of Physics Condensed Matter, Volume 35, issue 21

Abstract

The different superfluid phases of 3He are described by p-wave order parameters that include anisotropy axes both in the orbital and spin spaces. The anisotropy axes characterize the broken symmetries in these macroscopically coherent quantum many-body systems. The systems’ free energy has several degenerate minima for certain orientations of the anisotropy axes. As a result, spatial variation of the order parameter between two such regions, settled in different energy minima, forms a topological soliton. Such solitons can terminate in the bulk liquid, where the termination line forms a vortex with trapped circulation of mass and spin superfluid currents. Here we discuss possible soliton-vortex structures based on the symmetry and topology arguments and focus on the three structures observed in experiments: solitons bounded by spin-mass vortices in the B phase, solitons bounded by half-quantum vortices (HQVs) in the polar and polar-distorted A phases, and the composite defect formed by a half-quantum vortex, soliton and the Kibble-Lazarides-Shafi wall in the polar-distorted B phase. The observations are based on nuclear magnetic resonance (NMR) techniques and are of three types: first, solitons can form a potential well for trapped spin waves, observed as an extra peak in the NMR spectrum at shifted frequency; second, they can increase the relaxation rate of the NMR spin precession; lastly, the soliton can present the boundary conditions for the anisotropy axes in bulk, modifying the bulk NMR signal. Owing to solitons’ prominent NMR signatures and the ability to manipulate their structure with external magnetic field, solitons have become an important tool for probing and controlling the structure and dynamics of superfluid 3He, in particular HQVs with core-bound Majorana modes.

Description

Funding Information: We thank Grigori Volovik, Jaakko Nissinen, George Lazarides and Qaisar Shafi for useful discussions. This work was supported in part by Academy of Finland (Grant No. 332964), by the European Union’s Horizon 2020 research and innovation programme under Grant Agreement No. 824109, and by UK STFC Grant Number ST/T00682X/1. | openaire: EC/H2020/824109/EU//EMP

Keywords

composite topological defect, half-quantum vortex, spontaneous symmetry breaking

Other note

Citation

Mäkinen, J T, Zhang, K & Eltsov, V B 2023, ' Vortex-bound solitons in topological superfluid 3 He ', Journal of Physics Condensed Matter, vol. 35, no. 21, 214001, pp. 1-27 . https://doi.org/10.1088/1361-648X/acc227