Temperature dependence of the order parameter of the polar phase of liquid 3He in nematic aerogel

Abstract: It is shown that in the polar phase of superfluid 3 He, stabilized by nematic aerogel, at the condition of specular reflection of quasi-particles from the strands of aerogel the temperature dependence of the gap in the spectrum of quasi-particles coincides with that in the bulk polar phase without impurities. The analogy with the Anderson theorem for conventional superconductors is discussed.