Regensburg 2010 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 27: CE: Poster Session

TT 27.70: Poster

Mittwoch, 24. März 2010, 14:00–18:00, Poster D1

Generalized t-J models derived systematically from Hubbard models in the doped case — •Simone A. Hamerla and Götz S. Uhrig — Technische Universität Dortmund,Lehrstuhl für Theoretische Physik I, 44221 Dortmund, Germany

Fermionic Hubbard models are mapped to generalized t-J models by a systematic change of basis using self-similar continous unitary transformations (s-CUTs) [1].
In the new basis, charge fluctuations affecting the number of double occupancies are eliminated. The mapping relies on the energetic separation of sectors with different numbers of double occupancies. Thus this energy separation is calculated using the Liouville formalism. In this way we obtain the range of validity of the mapping for the first time in dependence of the doping.
Three different s-CUTs are investigated for various truncation schemes on linear chains and square lattices.

[1] A. Reischl, E. Müller-Hartmann, G. S. Uhrig, Phys. Rev. B 70, 245124