Dresden 2006 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 25: Correlated Electrons - Poster Session
TT 25.47: Poster
Mittwoch, 29. März 2006, 14:30–18:30, P1
Two-particle excitations in the Dynamical Cluster Approximation — •Stephan Hochkeppel, Fakher Assaad, and Werner Hanke — Theoretische Physik, Am Hubland, D-97074 Würzburg
The two-particle properties of the two-dimensional Hubbard model in the strong-coupling regime U=8t are investigated by using the Dynamical Cluster Approximation (DCA) [1]. In the DCA approach the original lattice problem is mapped to a self-consistently embedded cluster in momentum space. The crucial approximation of the DCA approach is to use the irreducible quantities, e.g the self-energy and irreducible vertices of a cluster as a good approximation of the lattice problem. We utilize a simplified Bethe-Salpeter equation with a renormalized Coulomb coupling Ueff(q→,iω) which is determined in the DCA scheme. First results are presented for the spin-excitation spectrum.
[1] M. Jarrell, Th. Maier, C. Huscroft, and S. Moukouri, Phys. Rev. B (2001).