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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 Andergassen^4,5 — 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