Triplet superfluidity in neutron matter with Skyrme forces at subnuclear and supranuclear densities in a strong magnetic field

Abstract

Abstract Within a generalized non-relativistic Fermi-liquid approach we have found general analytical formulae for phase-transition temperatures T c,1(n, H) and T c,2(n, H) (which are nonlinear functions of density, n, and linear of magnetic field, H) for phase transitions in spatially uniform, dense, pure neutron matter from normal to superfluid states with spin-triplet p-wave pairing (similar to anisotropic superfluid phases 3He - A1 and 3He - A2) in steady and homogeneous sufficiently strong magnetic field (but |µn|H ≪ E c < ɛ F(n), where µn is the magnetic dipole moment of a neutron, E c is the cutoff energy and ɛ F(n)is the Fermi energy in neutron matter). General formulae for T c,1,2(n,H) are valid for arbitrary parameterization of the effective Skyrme forces in neutron matter. We have used for definiteness the so-called SLy2, Gs and RATP parameterizations of the Skyrme forces with different exponents in their power dependence on density n (at sub- and supranuclear densities) from the interval 0.7 n 0 ≲ n < n c(Skyrme)< 2 n 0, where n 0 =0.17 fm−3 is the nuclear density and n c(Skyrme)is the the critical density of the ferromagnetic instability in superfluid neutron matter. These phase transitions might exist in the liquid outer core of magnetized neutron stars.