Fast summation of fermionic Feynman diagrams beyond Bravais Lattices and on-site Hubbard interactions

Boyuan Shi

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arXiv · 2504.06060

Fast summation of fermionic Feynman diagrams beyond Bravais Lattices and on-site Hubbard interactions

Boyuan Shi

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Abstract

We designed new algorithms for summing bold-line Feynman diagrams in arbitrary channels, where it can be readily modified for bare interaction series as well. When applied to magnetic channel bold-line series with on-site Hubbard interactions, the algorithm achieves competitive performance compared with the state-of-art RPADet. We then generalize it beyond square lattice and on-site Hubbard interactions and achieve better scaling in the number of sites within a unit cell, while there is substantial increase when there are more types of interactions. This work paves the way of diagrammatic Monte Carlo simulations for real materials, holding the premise for a robust replacement of state-of-art simulation tools in the thermodynamical limit.

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Boyuan Shi. 2025-04-08. Fast summation of fermionic Feynman diagrams beyond Bravais Lattices and on-site Hubbard interactions. https://arxiv.org/abs/2504.06060

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