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The single-impurity Anderson model is studied within the i-DFT framework, a recently proposed extension of density functional theory (DFT) for the description of electron transport in the steady state. i-DFT is designed to give both the…

Strongly Correlated Electrons · Physics 2017-01-11 S. Kurth , G. Stefanucci

The simulation of strongly correlated quantum impurity models is a significant challenge in modern condensed matter physics that has multiple important applications. Thus far, the most successful methods for approaching this challenge…

Strongly Correlated Electrons · Physics 2024-01-22 A. Erpenbeck , W. -T. Lin , T. Blommel , L. Zhang , S. Iskakov , L. Bernheimer , Y. Núñez-Fernández , G. Cohen , O. Parcollet , X. Waintal , E. Gull

We present improvements of a recently introduced numerical method [Arrigoni etal, Phys. Rev. Lett. 110, 086403 (2013)] to compute steady state properties of strongly correlated electronic systems out of equilibrium. The method can be…

Strongly Correlated Electrons · Physics 2015-12-22 Irakli Titvinidze , Antonius Dorda , Wolfgang von der Linden , Enrico Arrigoni

We review two analytical approaches in Dynamical Mean-Field Theory (DMFT) based on a perturbation theory expansion over the electron hopping to and from the self consistent environment. In the first approach the effective single impurity…

Strongly Correlated Electrons · Physics 2007-05-23 I. V. Stasyuk , A. M. Shvaika

We present a tensor network especially suited for multi-orbital Anderson impurity models and as an impurity solver for multi-orbital dynamical mean-field theory (DMFT). The solver works directly on the real-frequency axis and yields very…

Strongly Correlated Electrons · Physics 2017-07-26 Daniel Bauernfeind , Manuel Zingl , Robert Triebl , Markus Aichhorn , Hans Gerd Evertz

We propose a mixed-configuration approximation based on single-band impurity solvers to efficiently study nonequilibrium multi-orbital systems at moderate computational cost. In this work, we merge the approach with the so-called auxiliary…

Strongly Correlated Electrons · Physics 2025-07-16 Tommaso Maria Mazzocchi , Daniel Werner , Markus Aichhorn , Enrico Arrigoni

We derive an exact mapping from the action of nonequilibrium dynamical mean-field theory (DMFT) to a single-impurity Anderson model (SIAM) with time-dependent parameters, which can be solved numerically by exact diagonalization. The…

Strongly Correlated Electrons · Physics 2013-12-06 Christian Gramsch , Karsten Balzer , Martin Eckstein , Marcus Kollar

The accurate theoretical description of materials with strongly correlated electrons is a formidable challenge in condensed matter physics and computational chemistry. Dynamical Mean Field Theory (DMFT) is a successful approach that…

The convergence to the self-consistency in the dynamical-mean-field-theory (DMFT) calculations for models of correlated electron systems can be significantly accelerated by using an appropriate mixing of hybridization functions which are…

Strongly Correlated Electrons · Physics 2009-11-11 Rok Zitko

We propose an improved fast multi-orbital impurity solver for the dynamical mean field theory (DMFT) based on equations of motion (EOM) of Green's functions and decoupling scheme. In this scheme the inter-orbital Coulomb interactions are…

Strongly Correlated Electrons · Physics 2015-05-30 Qingguo Feng , P. M. Oppeneer

We solve the impurity problem which arises within nonequilibrium dynamical mean-field theory for the Hubbard model by means of a self-consistent perturbation expansion around the atomic limit. While the lowest order, known as the…

Strongly Correlated Electrons · Physics 2013-05-29 Martin Eckstein , Philipp Werner

We review recent developments in the theory of interacting quantum many-particle systems that are not in equilibrium. We focus mainly on the nonequilibrium generalizations of the flow equation approach and of dynamical mean-field theory…

Strongly Correlated Electrons · Physics 2010-06-16 M. Eckstein , A. Hackl , S. Kehrein , M. Kollar , M. Moeckel , P. Werner , F. A. Wolf

The study of nonequilibrium phenomena in correlated lattice systems has developed into an active and exciting branch of condensed matter physics. This research field provides rich new insights that could not be obtained from the study of…

Strongly Correlated Electrons · Physics 2014-07-11 Hideo Aoki , Naoto Tsuji , Martin Eckstein , Marcus Kollar , Takashi Oka , Philipp Werner

The development of numerical methods capable of simulating realistic materials with strongly correlated electrons, with controllable errors, is a central challenge in quantum many-body physics. Here we describe how a hybrid between…

Strongly Correlated Electrons · Physics 2015-04-23 Alexei A. Kananenka , Emanuel Gull , Dominika Zgid

We discuss the evaluation of the integrals for intermediate-order diagrams in the self-consistent strong-coupling expansion on the Keldysh contour using Tensor Cross Interpolation (TCI). TCI is used to factorize the nested parts of the…

Strongly Correlated Electrons · Physics 2024-10-28 Martin Eckstein

We present the first application of quantics tensor trains (QTTs) and tensor cross interpolation (TCI) to the solution of a full set of self-consistent equations for multivariate functions, the so-called parquet equations. We show that the…

Strongly Correlated Electrons · Physics 2025-04-29 Stefan Rohshap , Marc K. Ritter , Hiroshi Shinaoka , Jan von Delft , Markus Wallerberger , Anna Kauch

Dynamical mean-field theory (DMFT) is one of the most widely-used methods to treat accurately electron correlation effects in ab-initio real material calculations. Many modern large-scale implementations of DMFT in electronic structure…

Strongly Correlated Electrons · Physics 2019-06-05 Evan Sheridan , Cedric Weber , Evgeny Plekhanov , Christopher Rhodes

We use tensor network techniques to obtain high order perturbative diagrammatic expansions for the quantum many-body problem at very high precision. The approach is based on a tensor train parsimonious representation of the sum of all…

Near-term quantum processors are limited in terms of the number of qubits and gates they can afford. They nevertheless give unprecedented access to programmable quantum systems that can efficiently, although imperfectly, simulate quantum…

Strongly Correlated Electrons · Physics 2025-11-25 Thomas Ayral

We present a continuous-time Monte Carlo method for quantum impurity models, which combines a weak-coupling expansion with an auxiliary-field decomposition. The method is considerably more efficient than Hirsch-Fye and free of time…

Strongly Correlated Electrons · Physics 2008-06-02 Emanuel Gull , Philipp Werner , Olivier Parcollet , Matthias Troyer