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Preprints, Working Papers, ... Year : 2014

Beyond extended dynamical mean-field theory: dual boson approach to the two-dimensional extended Hubbard model

Erik G. C. P. van Loon
  • Function : Author
Alexander I. Lichtenstein
  • Function : Author
Mikhail I. Katsnelson
  • Function : Author
Hartmut Hafermann
  • Function : Author

Abstract

The dual boson approach [Ann. Phys. 327, 1320 (2012)] provides a means to construct a diagrammatic expansion around the extended dynamical mean-field theory (EDMFT). In this paper, we present the numerical implementation of the approach and apply it to the extended Hubbard model with nearest-neighbor interaction $V$. We calculate the EDMFT phase diagram and study the effect of diagrams beyond EDMFT on the transition to the charge-ordered phase. Including diagrammatic corrections to the EDMFT polarization shifts the EDMFT phase boundary to lower values of $V$. The approach interpolates between the random phase approximation in the weak coupling limit and EDMFT for strong coupling. Neglecting vertex corrections leads to results reminiscent of the EDMFT+$GW$ approximation. We however find significant deviations from the dual boson results already for small values of the interaction, emphasizing the crucial importance of fermion-boson vertex corrections.

Dates and versions

cea-01058818 , version 1 (28-08-2014)

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Erik G. C. P. van Loon, Alexander I. Lichtenstein, Mikhail I. Katsnelson, Olivier Parcollet, Hartmut Hafermann. Beyond extended dynamical mean-field theory: dual boson approach to the two-dimensional extended Hubbard model. 2014. ⟨cea-01058818⟩
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