  We develop a new ab initio many-body approach capable of describing
simultaneously both bound and scattering states in light nuclei, by combining
the resonating-group method with the use of realistic interactions, and a
microscopic and consistent description of the nucleon clusters. This approach
preserves translational symmetry and Pauli principle. We outline technical
details and present phase shift results for neutron scattering on 3H, 4He and
10Be and proton scattering on 3He and 4He, using realistic nucleon-nucleon (NN)
potentials. Our A=4 scattering results are compared to earlier ab initio
calculations. We find that the CD-Bonn NN potential in particular provides an
excellent description of nucleon-4He S-wave phase shifts. On the contrary, the
experimental nucleon-4He P-wave phase shifts are not well reproduced by any NN
potential we use. We demonstrate that a proper treatment of the coupling to the
n-10Be continuum is successful in explaining the parity-inverted ground state
in 11Be.
