Dresden 2026 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 13: Correlated Electrons: Method Development I
TT 13.4: Talk
Monday, March 9, 2026, 15:45–16:00, HSZ/0101
Cluster extension of the DMF2RG and application to the 2d Hubbard model — •Marcel Krämer1,2,3, Michael Meixner3, Kilian Fraboulet3, Demetrio Vilardi3, Pietro Bonetti4, Nils Wentzell5, Alessandro Toschi2, and Sabine Andergassen1,2 — 1Institute of Information Systems Engineering, TU Wien, Vienna, Austria — 2Institute for Solid State Physics, TU Wien, Vienna, Austria — 3Max Planck Institute for Solid State Research, Stuttgart, Germany — 4Department of Physics, Harvard University, Cambdrige, USA — 5Center for Computational Quantum Physics, Flatiron Institute, New York, USA
The DMF2RG has been introduced to overcome the weak-coupling limitation of the fermionic functional renormalization group (fRG). This approach builds on the idea of exploiting the dynamical mean-field theory (DMFT) as starting point for the fRG flow, thus capturing local non-perturbative correlations via DMFT together with perturbative non-local correlations generated during the flow. We show how non-local non-perturbative correlations can be incorporated in the DMF2RG scheme by employing solutions of non-local extensions of DMFT as a starting point of the flow. The one-loop fRG flow equations are formulated within the single-boson exchange decomposition (SBE), which classifies diagrams contributing to the two-particle vertex in terms of interaction reducibility and has been proven to be a powerful bosonization scheme. We illustrate the ability of this approach to capture non-local non-perturbative correlations in the 2d Hubbard model and summarize latest methodological advances.
Keywords: Hubbard Model; Dynamical mean-field theory; Functional renormalization group