Low-energy models for correlated materials: bandwidth renormalization   from Coulombic screening
  We provide a prescription for constructing Hamiltonians representing the low energy physics of correlated electron materials with dynamically screened Coulomb interactions. The key feature is a renormalization of the hopping and hybridization parameters by the processes that lead to the dynamical screening. The renormalization is shown to be non-negligible for various classes of correlated electron materials. The bandwidth reduction effect is necessary for connecting models to materials behavior and for making quantitative predictions for low-energy properties of solids. 
M. Casula, Ph. Werner, L. Vaugier, F. Aryasetiawan, A. J. Millis, S.   Biermann
cond-mat.str-el