Parquet approach - the <i>most fundamental </i>diagrammatic method?

ORAL

Abstract

In this talk we show that the parquet equation follows as natural and in fact completely analogous to well known diagrammatic equations like the Dyson or the Bethe-Salpeter equation. Furthermore, it has been shown that other well known methods like the GW approximation or the functional Renormalization Group (fRG) method emerge as ways to find an approximate solution to the parquet equation [1][2].
This makes the parquet approach a very fundamental one and raises interest in approximate solutions to the parquet equation.
We here present an approximate way to solve the parquet equation using the method of Truncated Unities[3]. We apply it to the 2D Hubbard model reaching temperatures and system sizes that were previously hardly accessible by unbiased methods. We find deviations from mean field behaviour like the pseudogap-phase.

[1] F. Krien, A. Kauch, K. Held, 2020 arXiv:2009.12868
[2] F. Kugler J. Delft, 2019 New J. Phys. 21 099601
[3] C. Eckhardt, C. Honerkamp, K. Held, A. Kauch, 2020 Phys. Rev. B 101, 155104

*This work has been supported in part by the Austrian Science Fund(FWF) through projects P 30997 and P 32044. CEand CH acknowledge support by Deutsche Forschungs-gesellschaft through the project DFG-RTG 1995.

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Presenters

  • Christian Eckhardt

    • Institut für Theoretische Festkörperphysik, RWTH Aachen University, Germany
    • Theory, Max Planck Institut for Structure and Dynamcis of Matter

Authors

  • Christian Eckhardt

    • Institut für Theoretische Festkörperphysik, RWTH Aachen University, Germany
    • Theory, Max Planck Institut for Structure and Dynamcis of Matter

  • Carsten Honerkamp

    • RWTH Aachen University
    • Theoretical Solid State Physics, RWTH Aachen University and JARA-FIT
    • Institute for Theoretical Solid State Physics, RWTH Aachen University

  • Patrick Kappl

    • Solid State Physics, TU Wien

  • Karsten Held

    • Solid State Physics, TU Wien

  • Anna Kauch

    • Institut für Festkörperphysik, TU Wien
    • Solid State Physics, TU Wien
    • Department of Solid State Physics, Vienna Univ of Technology