High-frequency asymptotic behavior of self-energies in quantum impurity   models
  We present explicit expressions for the high-frequency asymptotic behavior of electron self-energy of general quantum impurity models, which may be useful for improving the convergence of dynamical mean-field calculations and for the analytic continuation of the electron self-energy. We also give results, expressed in more physical terms, for the two-orbital and three-orbital rotationally invariant Slater-Kanamori interactions, in order to facilitate calculations of transition metal oxides. 
Xin Wang, Hung The Dang, Andrew J. Millis
cond-mat.str-el