MERCREDI 26 JANVIER 2005 16 heures Salle Séminaire 5 Centre de Physique Théorique Marseille-Luminy Arne Jensen Department of Mathematical Sciences Aalborg University Aalborg, Denmark Title: The Fermi Golden Rule at Thresholds Abstract: Assume that a Schrödinger operator has an eigenvalue embedded at a threshold. A perturbation may turn this eigenvalue into a resonance. We show how the Fermi Golden Rule has to be modified, in order to compute the imaginary part of the resonance for small coupling constants. Joint work with G. Nenciu.