Regensburg 2016 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 61: Correlated Electrons: (General) Theory 1
TT 61.9: Vortrag
Donnerstag, 10. März 2016, 11:45–12:00, H18
High-frequency aysmptotics of the local vertex function: algorithmic implementations — •Agnese Tagliavini1,2, Nils Wentzell1,2, Gang Li2, Ciro Taranto2,3, Georg Rohringer2, Karsten Held2, Alessandro Toschi2, and Sabine Andergassen1 — 1Institut für Theoretische Physik, Eberhard Karls Universität, 72076 Tübingen, Germany — 2Institute for Solid State Physics, Vienna University of Technology, 1040 Vienna, Austria — 3Max Planck Institute for Solid State Research, D-70569 Stuttgart, Germany
Local vertex functions are a crucial ingredient of several forefront many-body algorithms in condensed matter physics. However, the full treatment of their frequency dependence poses a huge limitation to the numerical performance. A significant advancement requires an efficient treatment of the high-frequency asymptotic behavior of the vertex functions. We here provide a detailed diagrammatic analysis of the high-frequency asymptotic structures and their physical interpretation. Based on these insights, we propose a frequency parametrization, which captures the whole high-frequency asymptotics for arbitrary values of the local Coulomb interaction and electronic density. We present its algorithmic implementation in many-body solvers based on parquet-equations as well as functional renormalization group schemes and assess its validity by comparing our results for the single impurity Anderson model with exact diagonalization calculations.