Superperturbation theory on the real-axis
  In this article we formulate the superperturbation theory for the Anderson impurity model on the real axis. The resulting impurity solver allows to evaluate dynamical quantities without numerical analytical continuation by the maximum entropy method or Pad\'e approximants. This makes the solver well suited to study multiplet effects in solids within the dynamical mean field theory. First examples including multi-orbital problems are discussed. 
Christoph Jung, Aljoscha Wilhelm, Hartmut Hafermann, Sergey Brener and   Alexander Lichtenstein
cond-mat.str-el