Two-particle-correlations in a functional renormalization group scheme using a dynamical mean-field theory approach

Abstract

We apply a recently introduced hybridization-flow functional renormalization group scheme for Anderson-like impurity models as an impurity solver in a dynamical mean-field theory (DMFT) approach to lattice Hubbard models. We present how this scheme is capable of reproducing metallic and insulating solutions of the lattice model. Our setup also offers a numerically rather inexpensive method to calculate two-particle correlation functions. For the paramagnetic Hubbard-model on the Bethe lattice in infinite dimensions we calculate the local two-particle-vertex for the metallic and the insulating phase. Then we go to a two-site cluster-DMFT-scheme for the two-dimensional Hubbard-model that includes short-range antiferromagnetic fluctuations and obtain the local and non-local two-particle-vertex-functions. We discuss the rich frequency structures of these vertices and compare with the vertex in the single-site solution.

22 pages, 15 figures

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Cited by in corpus (12)

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• From infinite to two dimensions through the functional renormalization group
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• Collective Charge Excitations of Strongly Correlated Electrons, Vertex Corrections and Gauge Invariance
• Self-energy and vertex functions from hybridization expansion continuous-time quantum Monte Carlo for impurity models with retarded interaction
• Correlated starting points for the functional renormalization group
• Fermionic two-loop functional renormalization group for correlated fermions: Method and application to the attractive Hubbard model
• Efficient Bethe-Salpeter equations' treatment in dynamical mean-field theory
• Efficient vertex parametrization for the constrained functional renormalization group for effective low-energy interactions in multiband systems
• Low-energy effective interactions beyond the constrained random-phase approximation by the functional renormalization group
• Approximating the frequency dependence of the effective interaction in the functional renormalization group for many-fermion systems
• Review of recent developments of the functional renormalization group for systems out of equilibrium