Dresden 2009 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 24: Correlated Electrons: (General) Theory 2

TT 24.1: Talk

Wednesday, March 25, 2009, 09:30–09:45, HSZ 301

Finite-Temperature Variational Cluster Approach (VCA) — •Gang Li, Maximilian Kiesel, and Werner Hanke — Institute for Theoretical Physics and Astrophysics, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany

The Variational Cluster Approach (VCA) proliferates the many-body physics, contained in an exact solution of a "reference system", i.e. a cluster, in a controlled manner to the infinite-system size limit of strongly correlated lattice models. This approach has been found for the 2D single-band Hubbard model to reproduce salient features of the (T=0) ground-state phase diagram [1], single-particle excitations [2] and, most recently, two-particle, i.e. magnetic excitations [3]. Here, we describe an implementation of the continuous-time QMC technique as a "cluster solver". This new method allows to consider finite temperature properties as well as a significantly large number of electronic (orbital) degrees of freedom in the underlying many-body model.

[1]. M. Aichhorn, E. Arrigoni, M. Potthoff, W. Hanke, Phys. Rev. B. 74, 024508 (2006).

[2] M. Aichhorn, E. Arrigoni, Z. B. Huang, W. Hanke, Phys. Rev. Lett. 99, 257002 (2007).

[3] S. Brehm, E. Arrigoni, M. Aichhorn, W. Hanke, arXiv: 0811.05213 (21.11.08).