Equation of Motion Solutions to Hubbard Model retaining Kondo Effect
  We propose a new way of analyzing the Hubbard model using equations of motion (EOM) for the higher-order Green's functions approach within the DMFT scheme. In calculating the higher order Green function we will differentiate over both Times (t) and (t'). This allows us to obtain the metallic Fermi liquid at nonzero Coulomb interaction, where the three center density of states (DOS) structure with two Hubbard bands and the quasiparticle resonance peak is obtained. At small Coulomb interactions and zero temperature the height of the quasiparticle resonance peak on the Fermi energy is constant similarly as in the full DMFT method with numerical (Quantum Monte Carlo) or with analytical (e.g. iterative perturbation theory) calculations. 
Grzegorz Gorski and Jerzy Mizia
cond-mat.str-el