Van der Waals equation of state for asymmetric nuclear matter

Abstract

The application of the van der Waals equation of state to the asymmetric nuclear matter is considered in a critical state region. The corrections to the van der Waals pressure and free energy due to the Fermi statistics are obtained starting from the Thomas - Fermi entropy expression which ensures the fulfilment of the Nernst theorem. The derived corrections account for the effective nucleon mass and neutron-proton isotopic asymmetry. The parameters of the van der Waals equation of state are deduced by taking the experimental value of critical temperature for symmetric nuclear matter and testing the model of van der Waals with statistics corrections included against the theory of Skyrme energy density functional. A critical line in pressure-temperature-composition space is considered. The incompressibility coefficient is determined along the critical line as a function of nuclear matter composition. A jump in the value of specific heat upon crossing a critical line is discussed.