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TT: Fachverband Tiefe Temperaturen

TT 28: Correlated Electrons: Theory 1

TT 28.9: Talk

Thursday, September 8, 2022, 12:00–12:15, H23

Nonlinear response theory and three-particle diagrams in strongly correlated systems — •Patrick Kappl, Friedrich Krien, Clemens Watzenböck, and Karsten Held — Institute of Solid State Physics, TU Wien, Austria

We study three-particle correlation functions of the Anderson impurity model by means of quantum Monte Carlo simulations in the hybridization expansion. We analyze the parameter regime in which vertex corrections beyond the bare bubble term become relevant for the three-particle correlator. Such three-particle correlators are hitherto by-and-large terra incognita and become relevant for the next level of diagrammatic extensions of dynamical mean-field theory. We here restrict ourselves to correlators consisting of three densities n and spins S_x,y,z. These are related to nonlinear response theory and its zero-frequency component to the density-dependence of the electronic compressibility.