Berlin 2024 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 86: Correlated Electrons: Method Development
TT 86.4: Vortrag
Freitag, 22. März 2024, 10:15–10:30, H 3007
Towards nonperturbative nonlocal correlations in the 2d Hubbard Model with the fRG — •Marcel Krämer1, Michael Meixner2, Kilian Fraboulet1, Pietro M. Bonetti2, Demetrio Vilardi2, Nils Wentzell3, Thomas Schäfer2, Alessandro Toschi4, and Sabine Andergassen4,5 — 1Institut für Theoretische Physik, Universität Tübingen, Germany — 2Max Planck Institute for Solid State Research, Stuttgart, Germany — 3Center for Computational Quantum Physics, Flatiron Institute, New York, USA — 4Institute for Solid State Physics, Vienna University of Technology, Austria — 5Institute of Information Systems Engineering, Vienna University of Technology, Austria
The DMF2RG has been introduced to overcome the weak-coupling limitation of the fermionic functional renormalization group (fRG). This approach builds on the idea to exploit the dynamical mean-field theory (DMFT) as starting point for the fRG flow, thus capturing local nonperturbative correlations via DMFT together with perturbative nonlocal correlations generated during the flow. We show how nonlocal nonperturbative correlations can be also incorporated in the DMF2RG scheme by using cellular DMFT (CDMFT) for a 2×2 cluster instead of single-site DMFT as starting point of the flow. Both CDMFT and fRG implementations have been formulated within the single-boson exchange decomposition, which has already proven to be an insightful bosonization scheme. We illustrate the ability of this novel approach to efficiently capture nonlocal nonperturbative correlations in the 2d Hubbard model.
Keywords: Strongly correlated electrons; Dynamical mean field theory; Functional renormalization group; Hubbard model; Unconventional superconductivity