2011/08/31 by Hartmut Hafermann, Kelly R. Patton, Philipp Werner · 6 citations
Materials Science · Mathematics · Physics and Astronomy · #Advanced Condensed Matter Physics #Estimator #Magnetic and transport properties of perovskites and related materials #Mathematics #Monte Carlo method #Physics #Physics of Superconductivity and Magnetism #Quantum Monte Carlo #Quantum mechanics #Statistical physics #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.85.205106
published as Phys. Rev. B 85, 205106 (2012) · published version; 16 pages, 20 figures
openalex publication_date 2012/05/03 · arxiv created 2012/05/30 · arxiv updated 2012/06/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We propose efficient measurement procedures for the self-energy and vertex function of the Anderson impurity model within the hybridization expansion continuous-time quantum Monte Carlo algorithm. The method is based on the measurement of higher-order correlation functions related to the quantities being sought through the equation of motion, a technique previously introduced in the numerical renormalization-group context. For the case of interactions of density-density type, the additional correlators can be obtained at essentially no additional computational cost. In combination with a recently introduced method for filtering the Monte Carlo noise using a representation in terms of orthogonal polynomials, we obtain data with unprecedented accuracy. This leads to an enhanced stability in analytical continuations of the self-energy or in two-particle-based theories such as the dual fermion approach. As an illustration of the method we reexamine the previously reported spin-freezing and high-spin to low-spin transitions in a two-orbital model with density-density interactions. In both cases, the vertex function undergoes significant changes, which suggests significant corrections to the dynamical mean-field solutions in dual fermion calculations.