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TT: Tiefe Temperaturen

TT 24: Postersitzung III: Korrelierte Elektronen, ”Orbital Physics”

TT 24.16: Poster

Mittwoch, 10. März 2004, 14:30–19:00, Poster A

General susceptibilities of highly correlated electron systems from a local point of view — •Sebastian Schmitt and Norbert Grewe — Institut für Festkörperphysik, Hochschulstraße 6, 64289 Darmstadt

Starting from a cumulant expansion in terms of the transfer between lattice sites in the presence of large local Coulomb matrix elements, Bethe-Salpeter equations are derived. Using only local particle-hole or particle-particle irreducible vertices, as in the dynamical mean field theory, general susceptibilities can be approximated. Employing a decoupling scheme for the energy summations, a typical Stoner-form is obtained, where the local interaction part is explicitly known.

In the case of the Hubbard model the magnetic susceptibility is studied in detail.