Dresden 2020 – wissenschaftliches Programm
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TT 62.2: Vortrag
Donnerstag, 19. März 2020, 15:15–15:30, HSZ 204
The role of the self-energy in the quantitative functional renormalization-group description of the two-dimensional Hubbard model — •Cornelia Hille1, Fabian B. Kugler2, Christian J. Eckhardt3,4,5, Yuan-Yao He6,7, Anna Kauch3, Daniel Rohe8, Carsten Honerkamp4,5, Alessandro Toschi3, and Sabine Andergassen1 — 1Universität Tübingen, Tübingen, Germany — 2LMU München, Munich, Germany — 3TU Vienna, Vienna, Austria — 4RWTH Aachen University, Aachen, Germany — 5JARA-FIT, Jülich Aachen, Germany — 6Flatiron Institute, New York, USA — 7College of William and Mary, Williamsburg, USA — 8Forschungszentrum Jülich GmbH, Jülich, Germany
The recently introduced multiloop extension of the functional renormalization group (fRG), which sums up all parquet diagrams with their exact weights, allows us to perform the first quantitative analysis for the 2D Hubbard model and to compare the results to the parquet approximation and determinant quantum Monte Carlo. We show that for convergence of the Truncated Unity fRG (form-factor expansion of the fermionic momentum dependence) to the solution of the parquet approximation, the self-energy flow has to be reformulated in analogy to the Schwinger-Dyson equation. The presented methodological improvement provides the basis towards quantitative predictions for more general systems. On a qualitative level, this new formulation is also crucially important for the description of single-particle properties such as the pseudogap opening.