CENPA Conference Room NPL-178

I discuss a rather different approach to effective interactions in which a single step is taken from QCD to a shell-model-like effective space, avoiding the usual construction of an NN potential (and subsequent steps to derive from the potential an interaction appropriate to the shell model). The scattering data previously used to construct the potential is instead used directly in the shell model. Key to doing this is the use of an energy-dependent interaction — which I will argue is as simple as standard effective interactions — that allows one to construct a theory that is analytically continuous in energy and generates the correct solution at every energy E (despite its use of a finite shell-model space). The theory also allows one to treat the pion — chiral symmetry — in a much simpler and more physical way than in conventional effective field theories: one keeps the long-range part that one needs, while not introducing fictitious singular behavior at short range.