Surrogate model solver for impurity-induced superconducting subgap states

A simple impurity solver is shown to capture the impurity-induced superconducting subgap states in quantitative agreement with the numerical renormalization group and quantum Monte-Carlo simulations. The solver is based on the exact diagonalization of a single-impurity Anderson model with discretize...

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Bibliographic Details
Published in:arXiv.org 2023-12
Main Authors: Baran, Virgil V, Frost, Emil J P, Paaske, Jens
Format: Article
Language:English
Subjects:
Couplings
Impurities
Phase diagrams
Solvers
Superconductivity
Online Access:Get full text
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Summary:A simple impurity solver is shown to capture the impurity-induced superconducting subgap states in quantitative agreement with the numerical renormalization group and quantum Monte-Carlo simulations. The solver is based on the exact diagonalization of a single-impurity Anderson model with discretized superconducting reservoirs including only a small number of effective levels. Their energies and couplings to the impurity \(d\)-level are chosen so as to best reproduce the Matsubara frequency dependence of the hybridization function. We provide a number of critical benchmarks and demonstrate the solvers efficiency in combination with the reduced basis method [Phys. Rev. B 107, 144503 (2023)] by calculating the phase diagram for an interacting three-terminal junction.
ISSN:2331-8422
DOI:10.48550/arxiv.2307.11646