Exploring universal characteristics of neutron star matter with relativistic <i>ab initio</i> equations of state

Starting from the relativistic realistic nucleon-nucleon ($NN$) interactions, a newly developed \textit{ab initio} method, i.e., Brueckner-Hartree-Fock (RBHF) theory in full Dirac space is employed to study neutron star properties. First, one-to-one correspondence relation for gravitational redshift and mass established used infer of isolated stars combining measurements. Next, ratio moment inertia $I$ $MR^2$ as function compactness $M/R$ obtained, which consistent with universal relations literature. The $1.338M_\odot$ pulsar PSR J0737-3039A $I_{1.338M_\odot}$ predicted be 1.356$\times10^{45}$, 1.381$\times10^{45}$, $1.407\times10^{45}\ \mathrm{g~cm^2}$ by RBHF $NN$ interactions Bonn A, B, C, respectively. Finally, quadrupole calculated under slow-rotation small-tidal-deformation approximation. equation states constructed space, together those projection method momentum-independence approximation, conform $I$-Love-$Q$ well. By combing tidal deformability GW170817 methods, 1.4 solar also deduced $I_{1.4M_\odot}=1.22^{+0.40}_{-0.25}\times 10^{45}\mathrm{g\ cm^2}$.