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TT: Tiefe Temperaturen

TT 25: Correlated Electrons - Poster Session

TT 25.29: Poster

Wednesday, March 29, 2006, 14:30–18:30, P1

Collective spin excitations within the time-dependent Gutzwiller approximation for the Hubbard model — •Falk Günther and Götz Seibold — BTU Cottbus

We use a spin-rotational invariant slave-boson-formulation of the Hubbard model, in order to investigate the collective excitations of itinerant ferromagnets. The expansion of the resulting spin-rotational invariant Gutzwiller energy functional around the saddle point allows the computation of dynamic correlation functions using the random-phase approximation (RPA). We evaluate ferromagnetic and antiferromagnetic instabilities from the transverse magnetic susceptibility and compute the dispersion relation for the spin waves. Results for one- and two-dimensional systems are presented and compared with the convetional Hartree-Fock+RPA theory.