Regensburg 2019 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 18: Frustrated Magnets - General 2 (joint session TT/MA)
MA 18.8: Vortrag
Dienstag, 2. April 2019, 15:45–16:00, Theater
Multi-loop contributions in the pseudo-fermion functional renormalization group for quantum spin systems: implementation and consequences — •Tobias Müller1, Yasir Iqbal2, Johannes Reuther3,4, and Ronny Thomale1 — 1Institute for Theoretical Physics and Astrophysics, Julius-Maximilians University of Würzburg, Am Hubland, D-97074 Würzburg, Germany — 2Department of Physics, Indian Institute of Technology Madras, Chennai 600036, India — 3Dahlem Center for Complex Quantum Systems and Institut für Theoretische Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany — 4Helmholtz-Zentrum für Materialien und Energie, Hahn-Meitner-Platz 1, 14019 Berlin, Germany
We extend the pseudo-fermion functional renormalization group (PFFRG) treatment of quantum spin systems by including diagrammatic higher loop contributions into the renormalization group flow. This allows us to consistently account for all contributions of parquet-type diagrams in the two-particle vertex and self-energy derivatives within the two-particle truncated PFFRG flow. We will discuss the impact of these corrections in different quantum spin models within PFFRG, especially in the light of the Mermin-Wagner theorem.