Together with Hugo Strand I have found a new numerical formalism for calculating real frequency response of a quantum impurity model, i.e. a local interacting degree of freedom coupled to a non-interacting continuum. The Kondo model or Anderson impurity model are archetypical examples. The method is based on stochastically sampling the non-interacting impurity bath Green’s function in terms of few level Anderson models that can be solved by exact diagonalization. The method is suitable for dynamical mean field theory (DMFT) where we believe it can give unprecedented real frequency resolution for multi-orbital/multi-site impurities with excellent correspondence to continuous-time quantum Monte Carlo results on the imaginary frequency axis.  arXiv:1201.6160  berlin120327.pdf