Oleksii Ivanytskyi
Early deconfinement of asymptotically conformal color-superconducting quark matter in neutron stars
I present a relativistic density functional approach to color superconducting quark matter, which mimics quark confinement by a fast growth of the quasiparticle self-energy. It can be mapped to a chiral quark matter model with medium dependent couplings which is applied to describe the high density regime of quark matter with a special emphasis on reaching the conformal limit of QCD. While the (pseudo-) scalar, vector-isoscalar and vector-isovector sectors of the model are fitted to the mesonic mass spectrum and to the vacuum phenomenology of QCD, the coupling strength in the diquark channel is defined using the Fierz transformation argument. The remaining ambiguity of the model parameters is reduced by comparing the asymptotics of the quark matter pressure normalized to the Stefan-Boltzmann limit with the perturbative QCD result. The approach is confronted with the observational constraints from measurements of mass, radius and tidal deformability of neutron stars. These constraints favor an early onset of deconfinement and color superconductivity in neutron stars with onset masses below one solar mass. We discuss also the QCD phase diagram whereby a new two-zone interpolation scheme for the construction of the hadron-to-quark matter transition is developed. The formation of color-superconducting quark matter is shown to drive the trajectories of its evolution in supernovae and neutron star mergers towards the regimes of temperature and density reached in terrestrial experiments with relativistic heavy-ion collisions.