Regensburg 2019 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 44: Correlated Electrons: Method Development
TT 44.5: Talk
Wednesday, April 3, 2019, 16:00–16:15, H7
Fermion-boson vertex within Dynamical Mean-Field Theory — •Erik van Loon1,2, Friedrich Krien3,4, Hartmut Hafermann5, Alexander Lichtenstein3, and Mikhail Katsnelson1 — 1Radboud University, Nijmegen, the Netherlands — 2University of Bremen, Bremen, Germany — 3University of Hamburg, Hamburg, Germany — 4SISSA, Trieste, Italy — 5Huawei Technologies, Paris, France
In the study of strongly interacting electrons, correlations on the two-particle level are becoming accessible. These correlation functions are generally rather complicated and cumbersome objects that lack a clear physical intuition. In this work, we study a particular two-particle correlation function that does have a clear intuition: the fermion-boson vertex. It describes the response of the Green's function (self-energy) when an external field is applied. As such, it displays interesting behaviour when the metal-insulator transition is approached. We provide several perspectives on this object, including Ward identities, sum rules, analytical continuation, and its role in diagrammatic extensions of Dynamical Mean-Field Theory.