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TT: Fachverband Tiefe Temperaturen

TT 8: CE: (General) Theory

TT 8.9: Vortrag

Montag, 22. März 2010, 16:15–16:30, H21

Vertex Function and Dynamical Spin-Susceptibilities from DMFT — •Andreas Dolfen and Erik Koch — German Research School for Simulation Sciences and RWTH Aachen University, Germany

DMFT providing a local approximation to the electronic self-energy readily gives one-body quantities such as the Green’s function. Two-body quantities like general dynamical susceptibilities are significantly harder to obtain.

Here we describe how to evaluate spin susceptibilities from an exact diagonalization impurity solver. First we construct the two-particle Green’s function of the impurity model and the corresponding local irreducible vertex function. Inserting the vertex and interacting electron propagator for the lattice model into the Bethe-Salpeter equation we obtain dynamical susceptibilities. This technique allows the direct calculation of the susceptibility on the real axis.

As example, we present results for the Periodic Anderson Model.