Regensburg 2010 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 27: CE: Poster Session

TT 27.47: Poster

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

Projected excitations in a generalized Gutzwiller approximation — •Andrea Di Ciolo and Claudius Gros — Institut fuer Theoretische Physik, Goethe Universitaet Frankfurt, Frankfurt am Main, Germany.

We extended the generalized Gutzwiller Approximation originally proposed in PRB 72, 144505 (2005) to study projected particle (hole) excitations for inhomogeneous systems with SDW and/or CDW.

This method allows to evaluate observables associated to a correlated state with one or more excitations: for single excitations, one can evaluate their tunnelling transition probabilities into the correlated state; for double excitations one can investigate the response of the system... This approach is conceptually very powerful, because it allows a model-independent analysis: this means that the results are due only to the physical properties of the trial state and not to the choice of a specifical Hamiltonian. The drawback is that the complete extension of the formalism is very challenging, because new Gutwiller factors arise beyond the standard ones, obtained for example in Supercond. Sci. Tech. 1, 36, (1988). In particular, one task is highly not trivial: the evaluation of the size of the Hilbert spaces associated to a physical correlated state and to auxiliary ones. In order to learn how to handle the subtleties of the extended scheme, we applied it first to the case of the AFM. These latter results can be compared to the experimental evidence for materials displaying a long-range AFM order.