Pairing correlations in nuclear matter with realistic interactions

Some aspects of the superfluidity in nuclear matter and neutron matter are numerically investigated by using realistic interactions. It is shown that the gap equation with bare pairing interaction contains the particle-particle correlations corresponding to the ladder diagrams. The effects of the short range part of the interaction on the gap function are discussed in momentum space in connection with the weak coupling approximation. Extending the BCS theory to coupled channels, it is found that the pairing between neutron and proton in the 3S1-3D1 channel is surprisingly large, of the order of about 10 MeV. ((orig.))