2019/06/12 by A. Kiss, Annamária Kiss · 4 citations
Mathematics · Physics and Astronomy · #Analytic continuation #Anderson impurity model #Band gap #Condensed matter physics #Continuation #Density of states #Electron #Kondo effect #Lattice (music) #Mathematical analysis #Mathematics #Padé approximant #Physics #Physics of Superconductivity and Magnetism #Quantum and electron transport phenomena #Quantum mechanics #Rare-earth and actinide compounds #Statistical physics #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.100.214417
published in Physical review. B./Physical review. B 100(21) (American Physical Society)
arxiv created 2019/06/12 · openalex created_date 2019/06/27 · openalex publication_date 2019/12/16 · arxiv updated 2019/12/25 · openalex updated_date 2026/08/05
The self-energy Pad'e approach is discussed as an analytic continuation of numerical methods that evaluate correlation functions in imaginary time. Instead of direct analytic continuation of the correlation functions, the Pad'e method is applied for the self-energy in this approach, which is then used for deriving the Green's functions at real energies. We demonstrate that the self-energy Pad'e approach is more stable and robust against statistical errors compared to the direct way. The characteristics and success of the self-energy Pad'e approach are analyzed by actual calculations for the illustrative examples of the noninteracting Anderson lattice and interacting Hubbard model. A zero-gap Kondo lattice model with linearly vanishing conduction electron density of states at the Fermi level is also studied by using the self-energy Pad'e approach as an analytic continuation. We investigate the properties of the Kondo insulating state including the dependence of the insulating gap on the Kondo coupling and coherence effects. Furthermore, we identify two energy scales from dynamic and thermodynamic quantities that are associated as a direct and an indirect gap in a band hybridization picture.