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TT: Fachverband Tiefe Temperaturen

TT 33: Postersession Correlated Electrons: Metal Insulator Transition, Spin Systems and Itinerant Magnets

TT 33.14: Poster

Wednesday, March 25, 2009, 14:00–18:00, P1A

A Functional Approach for the Spin Chain — •Stephan Filor and Thomas Pruschke — Institut für Theoretische Physik, Universität Göttingen

We set up a new approach to the physics of spin systems which uses a resolvent method originally proposed by Keiter and Kuramoto. In analogy to the Baym-Kadanoff formalism the latter introduced the partition sum of a system as a functional of the resolvent of the Hamiltonian and its so called generalized self-energy. This functional is the starting point for a variational cluster method which is based on Potthoffs self-energy functional approach. In a first step we apply our ansatz to a Heisenberg spin chain.