Variational method for infinite nuclear matter with the Paris potential

The energy per nucleon for infinite nuclear matter with the parametrized Paris potential is calculated using the variational method recently proposed by Takano and Yamada. Approximate energy expressions playing an important role in this variational method are refined for the Paris potential, and in particular for the quadratic momentum parts in it. Since this variational method without any constraints gives extreme overbinding, an effective theory also proposed in conjunction with the above-mentioned variational method is applied, in a modified manner, to the calculations for symmetric nuclear matter and neutron matter with the Paris potential, as well as the Hamada-Johnston and AV14 potentials. The obtained equation of state (EOS) for the Paris potential is, unlike the unrealistically soft EOS for the AV14 potential, capable of describing neutron stars with a reasonable maximum mass of 1.65M_⊙.