2020/08/31 by Friedrich Krien, Angelo Valli, Patrick Chalupa-Gantner +6
Mathematics · Physics and Astronomy · #Algorithm #Atomic and Subatomic Physics Research #Boson #Bosonization #Combinatorics #Fermion #Formalism (music) #Hubbard model #Mathematical physics #Mathematics #Physics #Physics of Superconductivity and Magnetism #Quantum and electron transport phenomena #Quantum mechanics #Residual #Solver #Superconductivity #Vertex (graph theory) #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.102.195131
published as Phys. Rev. B 102, 195131 (2020) · 13 pages + appendix, 15 figures
arxiv created 2020/11/18 · openalex publication_date 2020/11/18 · arxiv updated 2020/11/19 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06
We present and implement a parquet approximation within the dual-fermion formalism based on a partial bosonization of the dual vertex function which substantially reduces the computational cost of the calculation. The method relies on splitting the vertex exactly into single-boson exchange contributions and a residual four-fermion vertex, which physically embody, respectively, long- and short-range spatial correlations. After recasting the parquet equations in terms of the residual vertex, these are solved using the truncated-unity method of Eckhardt et al. [Phys. Rev. B 101, 155104 (2020)], which allows for a rapid convergence with the number of form factors in different regimes. While our numerical treatment of the parquet equations can be restricted to only a few Matsubara frequencies, reminiscent of Astretsov et al. [Phys. Rev. B 101, 075109 (2020)], the one- and two-particle spectral information is fully retained. In applications to the two-dimensional Hubbard model the method agrees quantitatively with a stochastic summation of diagrams over a wide range of parameters.