Superperturbation theory on the real axis

Jung, Christoph; Wilhelm, Aljoscha; Hafermann, Hartmut; Brener, S.; Lichtenstein, A. I.

doi:10.1002/andp.201100043

Cited by 2 publications

(2 citation statements)

References 21 publications

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“…For ∆ (N ) ν ≡ 0 and in the limit of small hybridization ∆ ν , it reproduces the noninteracting limit and the result of a first-order expansion of the Green's function in the hybridization: (Dai et al, 2005). The one-and two-particle Green's functions g 12 and χ 1234 of the reference system can be expressed in terms of the ED eigenvalues and matrix elements and can be analytically continued to the real axis (Jung et al, 2011). The naive expansion exhibits a causality problem, which can however be cured (Jung, 2010) by introducing a renormalization parameter (Krivenko et al, 2010).…”

Section: Df As a Cluster Solvermentioning

confidence: 67%

Diagrammatic routes to nonlocal correlations beyond dynamical mean field theory

et al. 2018

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Strong electronic correlations pose one of the biggest challenges to solid state theory. Recently developed methods that address this problem by starting with the local, eminently important correlations of dynamical mean field theory (DMFT) are reviewed. In addition, nonlocal correlations on all length scales are generated through Feynman diagrams, with a local two-particle vertex instead of the bare Coulomb interaction as a building block. With these diagrammatic extensions of DMFT long-range charge-, magnetic-, and superconducting fluctuations as well as (quantum) criticality can be addressed in strongly correlated electron systems. An overview is provided of the successes and results achieved mainly for model Hamiltonians and an outline is given of future prospects for realistic material calculations. PACS numbers: 71.10.-w,71.10.Fd,71.27.+a CONTENTS 42 5. One and zero dimensions 43 B. Heavy fermions and Kondo lattice model (KLM) 44 C. Falicov-Kimball (FK) model 45 D. Models of Disorder 47 E. Non-local interactions and multiorbitals 48 V. Open source implementations 51 VI. Conclusion and outlook 51 References 53 arXiv:1705.00024v2 [cond-mat.str-el]

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Section: Df As a Cluster Solvermentioning

confidence: 67%

Diagrammatic routes to nonlocal correlations beyond dynamical mean field theory

et al. 2018

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“…12. A common feature of all diagrammatic extensions is that they build upon the local (two-and more-particle) vertex and use it to construct non-local correlations in one-and two-particle quantities. These approaches allow for describing physical phenomena beyond the realm of DMFT, such as formation of a pseudogap [13][14][15][16][17][18] and (quantum) critical exponents [19][20][21][22] .…”

Section: Introductionmentioning

confidence: 99%

Role of three-particle vertex within dual fermion calculations

et al. 2017

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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 behavior of the self-energy correction is -surprisingly -even dominated by corrections stemming from the three-particle vertex.

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Superperturbation theory on the real axis

Cited by 2 publications

References 21 publications

Diagrammatic routes to nonlocal correlations beyond dynamical mean field theory

Diagrammatic routes to nonlocal correlations beyond dynamical mean field theory

Role of three-particle vertex within dual fermion calculations

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