High-performance functional Renormalization Group calculations for interacting fermions

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• 作者：J. Lichtenstein^a ; ^{lichtenstein@physik.rwth-aachen.de} ; D. Sá ; nchez de la Peñ ; a^a ; D. Rohe^b ; E. Di Napoli^c ; ^b ; ^f ; C. Honerkamp^a ; ^d ; S.A. Maier^a ; ^e
• 关键词：functional Renormalization Group ; Interacting fermions ; Hybrid parallelization ; Hubbard model
• 刊名：Computer Physics Communications
• 出版年：2017
• 出版时间：April 2017
• 年：2017
• 卷：213
• 期：Complete
• 页码：100-110
• 全文大小：728 K
• 卷排序：213

文摘

We derive a novel computational scheme for functional Renormalization Group (fRG) calculations for interacting fermions on 2D lattices. The scheme is based on the exchange parametrization fRG for the two-fermion interaction, with additional insertions of truncated partitions of unity. These insertions decouple the fermionic propagators from the exchange propagators and lead to a separation of the underlying equations. We demonstrate that this separation is numerically advantageous and may pave the way for refined, large-scale computational investigations even in the case of complex multiband systems. Furthermore, on the basis of speedup data gained from our implementation, it is shown that this new variant facilitates efficient calculations on a large number of multi-core CPUs. We apply the scheme to the t,t′t,t′ Hubbard model on a square lattice to analyze the convergence of the results with the bond length of the truncation of the partition of unity. In most parameter areas, a fast convergence can be observed. Finally, we compare to previous results in order to relate our approach to other fRG studies.