Nematic aerogels consist of nearly parallel strands. In liquid ³He in such aerogels, the strands lead to anisotropy of ³He quasiparticles scattering that makes favorable new superfluid phases: polar, polar-distorted A (PdA) and polar-distorted B  [1]. A distinctive feature of this work is that experiments were performed with ³He in two samples of nematic aerogel one of which was squeezed by 30% in the direction transverse to the strands. The squeezing leads to anisotropy in a plane perpendicular to the strands that can affect superfluid phases. It was found that the superfluid transition of ³He in both samples occurred into the non-chiral polar phase, where no qualitative difference between properties of nuclear magnetic resonance in ³He in these samples was found. The difference, however, has appeared on further cooling, after a transition to the chiral PdA phase. The results agree with theoretical expectations and provide an additional proof of existence of the polar phase of ³He in nematic aerogels. The obtained quantitative characteristics of the observed phases also agree with recent theoretical paper [2] where it was stated that Anderson theorem for s-wave superconductors is applicable to superfluid ³He in ideal nematic aerogel.

[1] V.V. Dmitriev, A.A. Senin, A.A. Soldatov, and A.N. Yudin, Phys. Rev. Lett. 115, 165304 (2015).

[2] I.A. Fomin, JETP 127, 933 (2018).

V.V. Dmitriev, M.S. Kutuzov, A.A. Soldatov, A.N. Yudin

JETP Letters 110, issue 11 (2019)