LAUSR

Properties of the liquid-gas (LG) phase transition of thermal nuclear matter are investigated within the relativistic Hartree-Fock (RHF) theory, focusing on the role played by the in-medium balance between nuclear attraction and repulsion. Applying the RHF Lagrangian PKA1, rather different critical properties and LG phase diagrams are obtained in contrast to the other popular relativistic Lagrangians. Aiming at such notable model deviations, a series of testing parametrizations $x{\ensuremath{\kappa}}_{\ensuremath{\rho}}$ (${\ensuremath{\kappa}}_{\ensuremath{\rho}}$ being the $\ensuremath{\rho}$-tensor coupling strength) are proposed to bridge PKA1 and other popular Lagrangians. Along the systematics from PKA1 to the $x{\ensuremath{\kappa}}_{\ensuremath{\rho}}$ series and further to other popular Lagrangians, it is illustrated that the in-medium balance of nuclear attraction and repulsion, manifested as various modeling of the nuclear in-medium effects, is essential for the van der Waals-like behaviors of thermal nuclear matter, in which the residual nuclear in-medium effects deduced from the dominant attractive and repulsive channels play a significant role. Our study paves a way to model the in-medium nuclear interactions from the thermal statistic aspects of nuclear systems, e.g., referring to the critical temperature from future delicate experiments.