Speaker
Description
I consider the thermal conductivity and shear viscosity of leptons (electrons and muons) in the nucleon NS cores where protons are in the superconducting state. Charged lepton collision frequencies are mainly determined by the transverse plasmon exchange and are mediated by the character of the transverse plasma screening. In superconducting neutron star core protons give the dominant contribution to the screening. In the previous works [Shternin & Yakovlev, Phys. Rev. D 75 103004 (2007); 78 063006 (2008)] the superconducting proton contribution to the transverse screening was considered in the Pippard limit $\Delta \ll \hbar q v_{\mathrm{F}p}$, where $\Delta$ is the proton pairing gap, $v_{\mathrm{F}p}$ is the proton Fermi velocity, and $\hbar q$ is the typical transferred momentum in collisions. However, for large critical temperatures (large $\Delta$) and relatively small densities (small $q$) the Pippard limit may become invalid. Here I revisit these calculations in the limit of not too high temperatures $T< 0.35T_{\mathrm{c}p}$, where $T_{\mathrm{c}p}$ is the critical temperature of the proton pairing and show [1] that the older calculations severely underestimated the screening in a certain range of the parameters appropriate to the NS cores. As a consequence, the values of the kinetic coefficients at $T\ll T_{\mathrm{c}p}$ are found to be smaller than in previous calculations.
[1] P.S. Shternin, 2018, arXiv:1805.06000
