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arXiv · 1710.00648

Role of three-particle vertex within dual fermion calculations

T. Ribic·P. Gunacker·S. Iskakov·M. Wallerberger·G. Rohringer·A. N. Rubtsov·E. Gull·K. Held
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Abstract

We investigate the influence of self-energy diagrams beyond the two-particle vertex level within dual fermion theory. Specifically, we calculate the local three-particle vertex and construct from it selected dual fermion self-energy corrections to dynamical mean field theory. For the two-dimensional Hubbard model, the thus obtained self-energy corrections are small in the parameter space where dual fermion corrections based on the two-particle vertex only are small. However, in other parts of the parameter space, they are of a similar magnitude and qualitatively different from standard dual fermion theory. The high-frequency behaviour of the self-energy correction is - surprisingly - even dominated by corrections stemming from the three-particle vertex.

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T. Ribic, P. Gunacker, S. Iskakov, M. Wallerberger, G. Rohringer, A. N. Rubtsov, E. Gull, K. Held. 2017-09-18. Role of three-particle vertex within dual fermion calculations. https://doi.org/10.1103/physrevb.96.235127

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