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arXiv · 1703.06505

Multiloop functional renormalization group that sums up all parquet diagrams

Fabian B. Kugler·Jan von Delft
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Abstract

We present a multiloop flow equation for the four-point vertex in the functional renormalization group (fRG) framework. The multiloop flow consists of successive one-loop calculations and sums up all parquet diagrams to arbitrary order. This provides substantial improvement of fRG computations for the four-point vertex and, consequently, the self-energy. Using the X-ray-edge singularity as an example, we show that solving the multiloop fRG flow is equivalent to solving the (first-order) parquet equations and illustrate this with numerical results.

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Fabian B. Kugler, Jan von Delft. 2017-03-19. Multiloop functional renormalization group that sums up all parquet diagrams. https://doi.org/10.1103/physrevlett.120.057403

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