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arXiv · 2211.02453

Renormalized Perturbation Theory for Fast Evaluation of Feynman Diagrams on the Real Frequency Axis

M. D. Burke·Maxence Grandadam·J. P. F. LeBlanc
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Abstract

We present a method to accelerate the numerical evaluation of spatial integrals of Feynman diagrams when expressed on the real frequency axis. This can be realized through use of a renormalized perturbation expansion with a constant but complex renormalization shift. The complex shift acts as a regularization parameter for the numerical integration of otherwise sharp functions. This results in an exponential speed up of stochastic numerical integration at the expense of evaluating additional counter-term diagrams. We provide proof of concept calculations within a difficult limit of the half-filled 2D Hubbard model on a square lattice.

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M. D. Burke, Maxence Grandadam, J. P. F. LeBlanc. 2022-11-04. Renormalized Perturbation Theory for Fast Evaluation of Feynman Diagrams on the Real Frequency Axis. https://doi.org/10.1103/physrevb.107.115151

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