Correlations in nuclear matter

We analyze the nuclear matter correlation properties in terms of the pair correlation function. To this aim we systematically compare the results for the variational method in the lowest-order constrained variational (LOCV) approximation and for the Bruekner-Hartree-Fock (BHF) scheme. A formal link between the Jastrow correlation factor of LOCV and the defect function (DF) of BHF is established and it is shown under which conditions and approximations the two approaches are equivalent. From the numerical comparison it turns out that the two correlation functions are quite close, which indicates in particular that the DF is approximately local and momentum independent. The equations of state (EOS) of nuclear matter in the two approaches are also compared. It is found that once the three-body forces (TBF) are introduced, the two EOS are fairly close, while the agreement between the correlation functions holds with or without TBF.