Jean-Pierre Julien (1,2) and Robert Albers (1)
1 LANL, Theoretical Division T-11, Los Alamos NM 87545, USA
2 Universite J. Fourier and CNRS Institut Neel, BP166, 38042 Grenoble

We suggest a new impurity solver for the DMFT based on a recursion process in an operators space, the so-called Liouville space. It is applicable at zero temperature limit. The Green function and the self-energy are developed as continued fractions expansions where the coefficients are energyindependent and determined step by step. This approach, in its first levels, enables to recover known approximations (Hartree-Fock, Hubbard I, Hubbard III) and is extendable further systematically to any level of accuracy.