Numerical comparison of three theories of nuclear matter

Abstract

Three independent evaluations of the ground-state energy of a simple model of nuclear matter are compared. The potential chosen is central, consisting of a state-independent hard core surrounded by a spin-dependent Serber square well with parameters adjusted to produce a fit of the low-energy two-nucleon data. A careful evaluation of the energy expectation value with respect to a Jastrow wave function is performed within the Fermi-hypernetted-chain scheme of Fantoni and Rosati. At the test point k F = 1.56 fm −1, the variational result lies about 2 MeV abovē the best available Fadé approximants to the R-matrix expansion for the energy. This may be regarded as excellent agreement, considering the state-independence of the assumed Jastrow correlations. An estimate of the correction to the variational result due to the state dependence of the realistic correlations is made within the framework of the method of correlated basis functions (CBF). Both theories, R- matrix-Pad e ́ and Jastrow-CBF, yield substantially more binding than lowest-order Brueckner theory based on the choice of a self-consistent hole potential and zero particle potential in intermediate states.