Abstract:
Stimulated by the results of NMR experiments with superfluid
$^3$He in “nematically ordered” aerogel
(R. Sh. Askhadullin, V. V. Dmitriev, D. A. Krasnikhin et al.,
Pis`ma v ZHETF, 95, 355 (2012))
we report on the
results of phenomenological analysis of stability of different phases of
superfluid $^3$He subjected to a strong homogeneous uniaxial anisotropy. On
a basis of this analysis we suggest a form of the order parameter for the new
ESP2 phase observed in the quoted experiments. In the weak coupling limit the
suggested order parameter approaches that of the axi-planar phase. We discuss
a possible experimental check of the proposed identification of the new
phase.