Correlations and spectral functions in asymmetric nuclear matter

The self-energy of nucleons in asymmetric nuclear matter is evaluated employing different realistic models for the nucleon-nucleon interaction. Starting from the Brueckner Hartree Fock approximation without the usual angle-average in the two-nucleon propagator the effects of the hole-hole contributions are investigated within the self-consistent Green's function approach. Special attention is paid to the isospin-dependence of correlations, which can be deduced from the spectral functions of nucleons in asymmetric matter. The strong components of the proton - neutron interaction lead in neutron-rich matter to a larger depletion for the occupation probability of proton states below the Fermi momentum.