Shell model for open quantum systems

The postulate of Fano to develop the configuration interaction description of weakly bound or unbound energy levels which would be fully symmetric treatment of bound, resonance, and scattering single-particle states has been realized recently with the development of a modern continuum shell model. We discuss salient non-perturbative effects of the configuration mixing induced by the configuration interaction in nuclear many body states near the dissociation limit (the particle-emission threshold), which find a natural formulation in the non-hermitian framework of the continuum shell model. (authors)