Low-momentum nucleon-nucleon interactions and shell-model calculations

In the last few years, the low-momentum nucleon-nucleon (NN) interaction Vlow-k derived from free-space NN potentials has been successfully used in shell-model calculations. Vlow-k is a smooth potential which preserves the deuteron binding energy as well as the half-on-shell T matrix of the original NN potential up to a momentum cutoff Lambda. In this paper, we test a new low-momentum NN potential derived from chiral perturbation theory at next-to-next-to-next-to-leading order with a sharp low-momentum cutoff at 2.1 fm(-1). Shell-model calculations for the oxygen isotopes using effective Hamiltonians derived from both types of low-momentum potential are performed. We find that the two potentials show the same perturbative behavior and yield very similar results.