http://arxiv.org/abs/1810.04901
We discuss the effect of strong magnetic field on neutron $^{3}P_{2}$ superfluidity. Based on the attraction in the $^{3}P_{2}$ pair of two neutrons, we derive the Ginzburg-Landau equation in the path integral formalism by adopting the bosonization technique and leave the next-to-leading order in the expansion of the magnetic field $B$. We determine the $(T,B)$ phase diagram with temperature $T$, comprising three phases: the uniaxial nematic (UN) phase for $B=0$, D${2}$-biaxial nematic (BN) and D${4}$-BN phases in the finite $B$ and strong $B$ such as magnetars, respectively, where D${2}$ and D${4}$ are dihedral groups. we find that, compared with the leading order in the magnetic field known before, the region of the D${2}$-BN phase in the $(T,B)$ plane is extended by the effect of the next-to-leading order terms of the magnetic field. We also present the thermodynamic properties, such as heat capacities and spin susceptibility, and find that the spin susceptibility is anisotropic in the D${2}$-BN phase and isotropic in the UN and D$_{4}$-BN phases. Those information will be useful to understand the internal structures of magnetars.
S. Yasui, C. Chatterjee and M. Nitta
Fri, 12 Oct 18
43/59
Comments: 11 pages, 3 figures