Resonances of (N +- 1)-particle systems in a dilated Green's function approach

The inclusion of dilatation transformations in the framework of the one-electron Green's function of many-body theory is discussed with regard to the calculation of resonance energies and withs of states containing N +- 1 particles. By this mathematical method it is possible to extend the applicability of highly successful standard techniques employing only square integrable basis sets to metastable states which are degenerate with true continuum states into which they disintegrate with characteristic lifetimes. (orig.)