Simplified Parquet Equations for the Anderson Impurity Model: Comparison with Numerically Exact Solutions |

V. Pokorný
^{a}, M. Žonda^{ b}, A. Kauch^{ a} and V. Janiš^{ a}^{a}Institute of Physics, Czech Academy of Sciences, Na Slovance 2, 182 21 Prague, Czech Republic
^{b}Department of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University in Prague, Ke Karlovu 5, 12116 Prague, Czech Republic |

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We use an analytic solver for the single-impurity Anderson model based on simplified parquet equations to describe the Kondo asymptotics. This scheme uses a two-particle self-consistency to control the strong-coupling Kondo critical behavior of this model at half filling. The equations can be written in the real-frequency representation, which gives us direct access to spectral functions unlike numerical schemes in the Matsubara formalism. We compare our results to those obtained by second-order perturbation theory, numerical renormalization group, and continuous-time quantum Monte Carlo in order to assess the reliability of this approximation. |

DOI: 10.12693/APhysPolA.131.1042 PACS numbers: 71.10.Fd, 72.15.Qm, 74.40.Kb |