CORRELATIONS AND PAIRING IN NUCLEAR-MATTER WITHIN THE NOZIERES-SCHMITT-RINK APPROACH

The influence of correlations on the critical temperature and density for the onset of superfluidity in nuclear matter is investigated withi n the scheme of Nozieres and Schmitt-Rink [1]. For symmetric nuclear m atter a smooth transition from Bose-Einstein condensation (BEG) of deu teron-like bound states at low densities and low temperatures to Barde en-Cooper-Schrieffer (BCS) pairing at higher densities is described. C ompared with the mean field approach a lowering of the critical temper ature is obtained for symmetric nuclear matter as well as for pure neu tron matter. The Mott transition in symmetric nuclear matter is discus sed. Regions in the temperature-density plane are identified where cor related pairs give the main contribution to the composition of the sys tem, so that approximations beyond the quasi-particle picture are requ ested.