Correlations and effective interactions in nuclear matter

The description of bulk properties of nuclear systems starting from realistic nucleon-nucleon (NN) interactions is along-standing and unsolved problem. Various models for the NN interaction have been developed, which describe theexperimental NN phase shifts up to the threshold for pion production with high accuracy[1, 2, 3, 4]. A general featureof all these interaction models are strong short-range and tensor components, which lead to corresponding correlationsin the nuclear many-body wave-function. Hartree-Fock mean-field theory, which represents the the lowest-ordermany-body calculations one can perform with such realistic NN interactions, fails to produce bound nuclei [5, 6] preciselybecause Hartree-Fock does not fully incorporate many-body correlation effects.That correlations beyond the mean field are important is supported by experiments exploring the spectral distribu-tion of the single-particle strength. One experimental fact found in all nuclei is the global depletion of the Fermi sea.A recent experiment from NIKHEF puts this depletion of the proton Fermi sea in