NMR of helical textures inHe3 A

Abstract

In weak superflow and/or parallel magnetic field, bulk ${}_{}{}^3{}_{}{}^{}\mathrm{He} A$ is expected to form a stable helical texture. The nuclear-magnetic-resonance response of that texture is studied with Leggett's theory of spin dynamics in the superfluid. Two longitudinal and four transverse resonances are found, but the dynamic susceptibility typically shows that only one of each type has appreciable spectral weight.