Controllable Precision of the Projective Truncation Approximation for Green's Functions

Abstract

Recently, we developed the projective truncation approximation for the equation of motion of two-time Green's functions (P. Fan et al., Phys. Rev. B 97, 165140 (2018)). In that approximation, the precision of results depends on the selection of operator basis. Here, for three successively larger operator bases, we calculate the local static averages and the impurity density of states of the single-band Anderson impurity model. The results converge systematically towards those of numerical renormalization group as the basis size is enlarged. We also propose a quantitative gauge of the truncation error within this method and demonstrate its usefulness using the Hubbard-I basis. We thus confirm that the projective truncation approximation is a method of controllable precision for quantum many-body systems.

arXiv comment9 pages, 6 figures. arXiv admin note: substantial text overlap with arXiv:1802.03864

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Cited by in corpus (5)

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• Spatial spin-spin correlations of the single-impurity Anderson model with a ferromagnetic bath
• Improved strong-coupling perturbation theory of the symmetric Anderson impurity model
• Self-Consistent Random Phase Approximation from Projective Truncation Approximation Formalism