Simplified Parquet Equations for the Anderson Impurity Model: Comparison with Numerically Exact Solutions
V. Pokornýa, M. Žonda b, A. Kauch a and V. Janiš a
aInstitute of Physics, Czech Academy of Sciences, Na Slovance 2, 182 21 Prague, Czech Republic
bDepartment 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