63 citations · 607 across the 21 of their papers we have counts for
21 papers
Screening and effective RPA-like charge susceptibility in the extended Hubbard model
Aiman Al-Eryani, Sarah Heinzelmann, Kilian Fraboulet +2
We generalize the recently introduced single-boson exchange formalism to nonlocal interactions. In the functional renormalization group application to the extended Hubbard model in…
Pairing boost from enhanced spin-fermion coupling in the pseudogap regime
Yang Yu, Sergei Iskakov, Emanuel Gull +2
We perform a fluctuation analysis of the pairing interaction in the hole-doped Hubbard model within the dynamical cluster approximation. Our analysis reveals that spin-fluctuation-…
Embedded multi-boson exchange: A step beyond quantum cluster theories
Dominik Kiese, Nils Wentzell, Igor Krivenko +3
We introduce a diagrammatic multi-scale approach to the Hubbard model based on the interaction-irreducible (multi-boson) vertex of a small cluster embedded in a self-consistent med…
Unambiguous fluctuation decomposition of the self-energy: pseudogap physics beyond spin fluctuations
Yang Yu, Sergei Iskakov, Emanuel Gull +2
Correlated electron systems may give rise to multiple effective interactions whose combined impact on quasiparticle properties can be difficult to disentangle. We introduce an unam…
Non-linear responses and three-particle correlators in correlated electron systems exemplified by the Anderson impurity model
Patrick Kappl, Friedrich Krien, Clemens Watzenböck +1
Three-particle correlators are relevant for, among others, Raman, Hall and non-linear responses. They are also required for the next order of approximations extending dynamical mea…
Non-perturbative intertwining between spin and charge correlations: A "smoking gun" single-boson-exchange result
Severino Adler, Friedrich Krien, Patrick Chalupa-Gantner +2
We study the microscopic mechanism controlling the interplay between local charge and local spin fluctuations in correlated electron systems via a thorough investigation of the gen…
The plain and simple parquet approximation: single- and multi-boson exchange in the two-dimensional Hubbard model
Friedrich Krien, Anna Kauch
The parquet approach to vertex corrections is unbiased but computationally demanding. Most applications are therefore restricted to small cluster sizes or rely on various simplifyi…
Explaining the pseudogap through damping and antidamping on the Fermi surface by imaginary spin scattering
Friedrich Krien, Paul Worm, Patrick Chalupa +2
The mechanism of the pseudogap observed in hole-doped cuprates remains one of the central puzzles in condensed matter physics. We analyze this phenomenon via a Feynman-diagrammatic…
Parametrizations of local vertex corrections from weak to strong coupling: importance of the Hedin three-leg vertex
Viktor Harkov, Alexander I. Lichtenstein, Friedrich Krien
In the study of correlated systems, approximations based on the dynamical mean-field theory (DMFT) provide a practical way to take local vertex corrections into account, which capt…
Fluctuation diagnostic of the nodal/antinodal dichotomy in the Hubbard model at weak coupling: a parquet dual fermion approach
Friedrich Krien, Alexander I. Lichtenstein, Georg Rohringer
We apply the boson exchange parquet solver for dual fermions to the half-filled Hubbard model on a square lattice at small interaction. Our results establish that, in this regime,…
Tiling with triangles: parquet and methods unified
Friedrich Krien, Anna Kauch, Karsten Held
The parquet formalism and Hedin's approach are unified into a single theory of vertex corrections, corresponding to an exact reformulation of the parquet equations in terms o…
Boson-Exchange Parquet Solver for dual fermions
Friedrich Krien, Angelo Valli, Patrick Chalupa +3
We present and implement a parquet approximation within the dual-fermion formalism based on a partial bosonization of the dual vertex function which substantially reduces the compu…
The Bethe-Salpeter equation at the critical end-point of the Mott transition
Erik G. C. P. van Loon, Friedrich Krien, Andrey A. Katanin
Strong repulsive interactions between electrons can lead to a Mott metal-insulator transition. The Dynamical Mean-Field Theory (DMFT) explains the critical end-point and hysteresis…
Parquet-like equations for the Hedin three-leg vertex
Friedrich Krien, Angelo Valli
Taking the competition and the mutual screening of various bosonic fluctuations in correlated electron systems into account requires an unbiased approach to the many-body problem.…
Single-boson exchange decomposition of the vertex function
Friedrich Krien, Angelo Valli, Massimo Capone
We present a decomposition of the two-particle vertex function of the single-band Anderson impurity model which imparts a physical interpretation of the vertex in terms of the exch…
Efficient evaluation of the polarization function in dynamical mean-field theory
Friedrich Krien
The dynamical susceptibility of strongly correlated electronic systems can be calculated within the framework of the dynamical mean-field theory (DMFT). The required measurement of…
Two-particle Fermi liquid parameters at the Mott transition: Vertex divergences, Landau parameters, and incoherent response in dynamical mean-field theory
Friedrich Krien, Erik G. C. P. van Loon, Mikhail I. Katsnelson +2
We consider the interaction-driven Mott transition at zero temperature from the viewpoint of microscopic Fermi liquid theory. To this end, we derive an exact expression for the Lan…
Fermion-boson vertex within Dynamical Mean-Field Theory
Erik G. C. P. van Loon, Friedrich Krien, Hartmut Hafermann +2
In the study of strongly interacting systems, correlations on the two-particle level are receiving more and more attention. In this work, we study a particular two-particle correla…
Effective Heisenberg model and exchange interaction for strongly correlated systems
E. A. Stepanov, S. Brener, F. Krien +3
We consider the extended Hubbard model and introduce a corresponding Heisenberg-like problem written in terms of spin operators. The derived formalism is reminiscent of Anderson's…
Exact diagonalization solver for the extended dynamical mean-field theory
Darya Medvedeva, Sergei Iskakov, Friedrich Krien +2
We present an efficient exact diagonalization scheme for the extended dynamical mean-field theory and apply it to the extended Hubbard model on the square lattice with nonlocal cha…
Double occupancy in DMFT and the Dual Boson approach
Erik G. C. P. van Loon, Friedrich Krien, Hartmut Hafermann +3
We discuss the calculation of the double occupancy using Dynamical Mean-Field Theory (DMFT) in finite dimensions. The double occupancy can be determined from the susceptibility of…