Embedded multi-boson exchange: A step beyond quantum cluster theories

We introduce a diagrammatic multi-scale approach to the Hubbard model based on the interaction-irreducible (multi-boson) vertex of a small cluster embedded in a self-consistent medium. The vertex captures short-range correlations up to the length scale of the cluster, while long-range correlations a...

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Bibliographic Details
Published in:Physical review research 2024-11, Vol.6 (4), p.043159, Article 043159
Main Authors: Kiese, Dominik, Wentzell, Nils, Krivenko, Igor, Parcollet, Olivier, Held, Karsten, Krien, Friedrich
Format: Article
Language:English
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Summary:We introduce a diagrammatic multi-scale approach to the Hubbard model based on the interaction-irreducible (multi-boson) vertex of a small cluster embedded in a self-consistent medium. The vertex captures short-range correlations up to the length scale of the cluster, while long-range correlations are recovered from a set of diagrammatic equations for the Hedin three-leg vertex. By virtue of the crossing symmetry, the Fierz decoupling ambiguity of the Hubbard interaction is resolved exactly. Our benchmarks for the half-filled Hubbard model on the square lattice are in very good agreement with numerically exact diagrammatic Monte Carlo simulations.
ISSN:2643-1564
2643-1564
DOI:10.1103/PhysRevResearch.6.043159