Short-range correlations and the A-representability problem within the low-order approximation to the Jastrow method

Analytical expressions for the one-body density matrix and the related characteristics of closed s-d shell nuclei are obtained within the low-order approximation (LOA) to the Jastrow correlation method (JCM). The resulting local densities and elastic form factors are in agreement with the experimental data and associated nucleon momentum distributions are consistent with the calculated ones, using the much more complicated exp(S)-method. The correlation effects on the nucleon momentum and density distributions as well as the occupation numbers and the depletion of the Fermi sea are discussed. The short-range correlation accounted for in LOA of the JCM cause a depletion of the nuclear Fermi sea of about 4-8% for closed s-d shell nuclei. The resulting occupation of the states above the Fermi level forms the proper significant high-momentum tail of n(k). A violation of the A-representability condition for the one-body density matrix appears and the JCM in LOA fails to reproduce the first single particle states above the Fermi level whose angular momentum l is among the angular momenta of the states occupied in the uncorrelated ground state of nuclei. The closed analytical expression obtained for the one-body nuclear characteristics can be used to analyze the short-range correlation effects observed in the measured experimental data. 1 fig., 1 tab., 17 refs. (orig.)