Robust analytic continuation of Green's functions via projection, pole estimation, and semidefinite relaxation

Abstract

Green's functions of fermions are described by matrix-valued Herglotz-Nevanlinna functions. Since analytic continuation is fundamentally an ill-posed problem, the causal space described by the matrix-valued Herglotz-Nevanlinna structure can be instrumental in improving the accuracy and in enhancing the robustness with respect to noise. We demonstrate a three-pronged procedure for robust analytic continuation called PES: (1) Projection of data to the causal space. (2) Estimation of pole locations. (3) Semidefinite relaxation within the causal space. We compare the performance of PES with the recently developed Nevanlinna and Carathéodory continuation methods and find that PES is more robust in the presence of noise and does not require the usage of extended precision arithmetics. We also demonstrate that a causal projection improves the performance of the Nevanlinna and Carathéodory methods. The PES method is generalized to bosonic response functions, for which the Nevanlinna and Carathéodory continuation methods have not yet been developed. It is particularly useful for studying spectra with sharp features, as they occur in the study of molecules and band structures in solids.

14 pages, 5 figures

References in corpus (11)

• Nevanlinna Analytical Continuation
• Updated Core Libraries of the ALPS Project
• Progress on stochastic analytic continuation of quantum Monte Carlo data
• Analytical Continuation of Matrix-Valued Functions: Carathéodory Formalism
• Fully Self-Consistent Finite-Temperature $GW$ in Gaussian Bloch Orbitals for Solids
• Density functional plus dynamical mean field theory of the metal-insulator transition in early transition metal oxides
• Pairing Glue in the Two Dimensional Hubbard Model
• Relativistic Self-Consistent $GW$: Exact Two-Component Formalism with One-Electron Approximation for Solids
• Analytic continuation from limited noisy Matsubara data
• Robust analytic continuation combining the advantages of the sparse modeling approach and Padé approximation
• Maximum entropy analytic continuation for frequency-dependent transport coefficients with non-positive spectral weight

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