Equal-Spin Pairing State of Superfluid ${}^3$He in Aerogel

Abstract

The equal-spin pairing (ESP) state, the so-called A-like phase, of superfluid ${}^3$He in aerogels is studied theoretically in the Ginzburg-Landau (GL) region by examining thermodynamics, and the resulting equilibrium phase diagram is mapped out. We find that, among the ABM, planar, and robust pairing states, the ABM state with presumably quasi long-ranged superfluid order is the best candidate of the A-like phase with a strange lowering of the polycritical point (PCP) observed experimentally.

4 pages, 1 figure, one reference added, accepted for publication in Phys. Rev. B