Low-momentum nucleon-nucleon interaction and its application to few-nucleon systems

Low-momentum nucleon-nucleon interactions are derived within the framework of a unitary-transformation theory, starting with realistic nucleon-nucleon interactions. A cutoff momentum L is introduced to specify a border between the low- and high-momentum spaces. By Faddeev-Yakubovsky calculations the lowmomentum interactions are investigated with respect to the dependence of ground-state energies of 3H and 4He on the parameter L. It is found that we need the momentum cutoff parameter Lù5 fm−1 in order to reproduce satisfactorily the exact values of the binding energies for 3H and 4He. The calculation with L=2 fm−1 recommended by Bogner et al. leads to considerable overbinding at least for few-nucleon systems