| speaker: | Alex C. Hewson |
| time: | Fr. 11.04.03, 11:20 - 12:10 |
We present numerical renormalization group calculations for the dynamic response functions for a single impurity Anderson model coupled to a local phonon mode (Anderson-Holstein model). The results are interpreted in terms of atomic limit calculations, and perturbation theory for effective models appropriate for the various parameter regimes. Results for the lattice Holstein model at half-filling, based on dynamical mean field theory, will also be presented. We discuss in particualr the emergence of a low energy mode in the phonon spectrum at intermediate coupling, and the development of an energy gap in the one electron spectral density.