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TT: Tiefe Temperaturen

TT 26: Korrelierte Elektronen: Theorie II

TT 26.10: Vortrag

Donnerstag, 11. März 2004, 12:00–12:15, H18

Contractor Renormalization Group Calculation for the Hubbard model including Fermionic and Bosonic excitations. — •Sascha Brehm¹, Enrico Arrigoni^1,2, and Werner Hanke¹ — ¹Institut für Theoretische Physik und Astrophysik, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany — ²Institut für Theoretische Physik, Technische Universität Graz, Petersgasse 16, A-8010 Graz, Austria

We apply the contractor renormalization group technique (CORE) to extract a low-energy effective Hamiltonian for the 2-D Hubbard model. In contrast to earlier studies₁ we explicitly incorporate both bosonic and fermionic low-energy excitations. It is shown that one basic effect of the latter is to effectively enhance the hopping probability of the charge-(pair-)excitations with increasing Hubbard U interactions. The low-energy Hamiltonian is then solved with slave-boson techniques.

[1] E.Altman and A.Auerbach, Phys.Rev.B 65, 104508 (2002)