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TT: Tiefe Temperaturen

TT 7: Correlated Electrons - (General) Theory II

TT 7.4: Talk

Friday, March 4, 2005, 17:30–17:45, TU H2053

Contractor Renormalization Group Approach to the Strongly-Correlated Hubbard Model — •Sascha Brehm¹, Enrico Arrigoni^2,1, 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

In a first step, we apply the Contractor Renormalization Technique (CORE) to the 2-D Hubbard Model including bosonic plus fermionic excitations. The resulting Plaquette Boson-Fermion Model (PBFM) displays even qualitative changes (screening,etc.) compared to the so far exclusively considered purely bosonic Plaquette Model (E.Altman and A.Auerbach, Phys.Rev.B 65, 104508 (2002)). This is also shown in the case of the inter-layer Cooper-pair tunnelling theory. The phase diagram for the competing phases is then calculated within the slave-boson technique.