Bridging the gap: effective interactions from microscopic dynamics

I discuss the derivation of an effective interaction, obtained from a realistic nuclear Hamiltonian using the formalism of Correlated Basis Functions (CBF) and the cluster expansion technique. Unlike the bare nucleon-nucleon potential, this effective interaction is well behaved, and suitable for carrying out perturbative calculations of a variety of equilibrium and non-equilibrium properties of nuclear matter using the basis of eigenstates of the non interacting system. The robustness and accuracy of the proposed approach are thoroughly examined, comparing the results of its application to the Femi hard-sphere system to the predictions of low-density expansions. Selected properties of nuclear matter, at both zero and nonzero temperatures, are reported and discussed. (paper)