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Quantitative functional renormalization-group description of the two-dimensional Hubbard model by Hille, Cornelia; Kugler, Fabian B.; Eckhardt, Christian J.; He, Yuan-Yao; Kauch, Anna; Honerkamp, Carsten; Toschi, Alessandro; Andergassen, Sabine is a scholarly article available to read on EtoBox.

Using a leading algorithmic implementation of the functional renormalization group (fRG) for interacting fermions on two-dimensional lattices, we provide a detailed analysis of its quantitative reliability for the Hubbard model. In particular, we show that the recently introduced multiloop extension of the fRG flow equations for the self-energy and two-particle vertex allows for a precise match with the parquet approximation also for two-dimensional lattice problems. The refinement with respect to previous fRG-based computation schemes relies on an accurate treatment of the frequency and momentum dependences of the two-particle vertex, which combines a proper inclusion of the high-frequency asymptotics with the so-called truncated unity fRG for the momentum dependence. The adoption of the latter scheme requires, as an essential step, a consistent modification of the flow equation of the self-energy. We quantitatively compare our fRG results for the self-energy and momentum-dependent susceptibilities and the corresponding solution of the parquet approximation to determinant quantum Monte Carlo data, demonstrating that the fRG is remarkably accurate up to moderate interaction strengt

Author

Hille, Cornelia; Kugler, Fabian B.; Eckhardt, Christian J.; He, Yuan-Yao; Kauch, Anna; Honerkamp, Carsten; Toschi, Alessandro; Andergassen, Sabine

Published

2020

Language

EN