Berlin 2015 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 86: Correlated Electrons: (General) Theory 2
TT 86.9: Vortrag
Donnerstag, 19. März 2015, 11:45–12:00, H 3005
Correlated starting points for the functional renormalization group — •Nils Wentzell1,2,3, Ciro Taranto3, Andrey Katanin4,5, Alessandro Toschi3, and Sabine Andergassen1,2 — 1Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090 Vienna, Austria — 2Institut für Theoretische Physik and CQ Center for Collective Quantum Phenomena, Universität Tübingen, Auf der Morgenstelle 14, D-72076 Tübingen, Germany — 3Institute for Solid State Physics, Vienna University of Technology, 1040 Vienna, Austria — 4Institute of Metal Physics, Kovalevskaya Str., 18, 620990, Ekaterinburg, Russia — 5Ural Federal University, 620002, Ekaterinburg, Russia
We present a general frame to extend functional renormalization group (fRG) based computational schemes by using an exactly solvable interacting reference problem as starting point for the RG flow. The systematic expansion around this solution accounts for a non-perturbative inclusion of correlations. Introducing auxiliary fermionic fields by means of a Hubbard-Stratonovich transformation, we derive the flow equations for the auxiliary fields and determine the relation to the conventional weak-coupling truncation of the hierarchy of flow equations. As a specific example we consider the dynamical mean-field theory (DMFT) solution as reference system, and discuss the relation to the recently introduced DMF2RG and the dual-fermion formalism.