1301.7546 (G. Rohringer et al.)

One-particle irreducible functional approach - a new route to
diagrammatic extensions of DMFT    [PDF]

G. Rohringer, A. Toschi, H. Hafermann, K. Held, V. I. Anisimov, A. A. Katanin

We present an approach which, on the basis of the one-particle irreducible (1PI) generating functional formalism, includes electronic correlations on all length-scales beyond the local correlations of dynamical mean field theory. This formalism allows us to unify aspects of the dynamical vertex approximation (D\Gamma A) and the dual fermion (DF) scheme. In particular, it includes one-particle reducible contributions from the three- and more-particle vertices in the dual fermion approach, as well as some diagrams not included in the ladder version of D\Gamma A. To demonstrate the applicability and physical content of the 1PI approach, we compare the diagrammatics of 1PI, DF and D\Gamma A, as well as the numerical results of these approaches for the half-filled Hubbard model in two dimensions.

View original: http://arxiv.org/abs/1301.7546