Regensburg 2016 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 61: Correlated Electrons: (General) Theory 1

TT 61.7: Vortrag

Donnerstag, 10. März 2016, 11:00–11:15, H18

High-order diagrammatic expansion for the Gutzwiller wave function — Marc Alexander and •Marcus Kollar — Theoretical Physics III, Center for Electronic Correlations and Magnetism, University of Augsburg

Variational wave functions can provide insights into the physics of correlated electrons, but even the evaluation of static expectation values is notoriously difficult for many-body Hamiltonians. Usually stochastic or perturbative calculations are required, except for a few exact solutions in one or infinite dimensions. For the single-band Hubbard model a diagrammatic formulation for expectation values with the Gutzwiller wave function was developed [1,2], involving the same Feynman diagrams as φ⁴ field theory. The Feynman diagrams for the latter problem can be generated by computer [3], which we convert and evaluate to high order for the Gutzwiller wave function. Possible applications to equilibrium and nonequilibrium problems are discussed.
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