Half-quantum vortices in nematic and chiral phases of 3He

We report theoretical results for the stability of half-quantum vortices (HQVs) in the superfluid phases of He-3 confined in highly anisotropic Nafen aerogel. Superfluidity of He-3 confined in Nafen is the realization of a nematic superfluid with Cooper pairs condensed into a single p-wave orbital aligned along the anisotropy axis of the Nafen aerogel. In addition to the nematic phase, we predict a second chiral phase that onsets at a lower transition temperature. This chiral phase spontaneously breaks time-reversal symmetry and is a topological superfluid. Both superfluid phases are equal-spin pairing condensates that host arrays of HQVs as equilibrium states of rotating superfluid He-3. We present results for the structure of HQVs, including magnetic and topological signatures of HQVs in both the nematic and chiral phases of He-3-Nafen.

Automated summary

Theoretical results on the stability of half-quantum vortices (HQVs) in highly anisotropic Nafen aerogel-confined He-3 superfluid phases are reported. Two superfluid phases, a nematic superfluid and a chiral superfluid, are identified in He-3-Nafen, both hosting arrays of HQVs as stable states. These HQVs have distinct magnetic and topological signatures in the nematic and chiral phases of He-3-Nafen.