Berlin 2008 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 32: Correlated Electrons: Poster Session

TT 32.3: Poster

Donnerstag, 28. Februar 2008, 14:00–18:00, Poster B

Quantum Phase Transitions in the Bosonic Single-Impurity Anderson Model — •Hyun-Jung Lee and Ralf Bulla — Theoretische Physik III, Elektronische Korrelationen und Magnetismus, Institut für Physik, Universität Augsburg, D-86135 Augsburg,*Germany

We consider a quantum impurity model in which a bosonic impurity level is coupled to a non-interacting bosonic bath, with the bosons at the impurity site subject to a local Coulomb repulsion U. Numerical renormalization group calculations for this bosonic single-impurity Anderson model reveal a zero-temperature phase diagram where Mott phases with reduced charge fluctuations are seperated from a Bose-Einstein condensed phase by lines of quantum critical points. We investigate the dynamics of the impurity model in various circumstances and prepare the ground for the dynamical mean-field theory of the Bose-Hubbard model.