Renormalization group analysis of spectral problems in quantum field theory (Q1269456)

A new renormalization group technique is described in detail and mathematically selfcontained. In this theory, the renormalization group transformation acts directly on a space of operators. Spectral properties of Hamiltonians are studied which generate the time evolution of atomic systems with electrons bound to static nuclei and interacting with a quantized radiation field. It is shown e.g. when excited atomic states turn into resonances. The topics in the sections of this article are: Description of the model and spectral results, the analysis of Feshbach maps, elimination of particle- and high photon-energy degrees of freedom, description of an inductive renormalization group construction and their spectral consequences.