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We examine the quality of the local self-energy approximation, applied here to models of multiple quantum impurities coupled to an electronic bath. The local self-energy is obtained by solving a single-impurity Anderson model in an…

Strongly Correlated Electrons · Physics 2015-10-05 Andrew K. Mitchell , Ralf Bulla

We generalize the dynamical-mean field (DMFT) approximation by including into the DMFT equations some length scale via a (momentum dependent) ``external'' self-energy \Sigma_k. This external self-energy describes non-local dynamical…

Strongly Correlated Electrons · Physics 2007-08-29 M. V. Sadovskii , I. A. Nekrasov , E. Z. Kuchinskii , Th. Pruschke , V. I. Anisimov

We present a new algorithm which is named the Dynamical Functional Particle Method, DFPM. It is based on the idea of formulating a finite dimensional damped dynamical system whose stationary points are the solution to the original…

Numerical Analysis · Mathematics 2013-03-25 Mårten Gulliksson , Sverker Edvardsson , Andreas Lind

Hyperuniform particle arrangements are characterized by a local number variance that grows more slowly than the volume of the observation window. We generalize this concept to describe particle systems in which particles carry weights:…

Statistical Mechanics · Physics 2026-03-04 Salvatore Torquato , Jaeuk Kim , Michael A. Klatt , Roberto Car , Paul J. Steinhardt

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 capture, respectively, particle-particle screening at weak…

Strongly Correlated Electrons · Physics 2021-10-06 Viktor Harkov , Alexander I. Lichtenstein , Friedrich Krien

We introduce regular series expansion for weakly- and moderately-correlated fermionic systems, based on Fluctuating Local Field approach. The method relies on the explicit account of leading fluctuating mode(s) and is therefore suitable for…

Strongly Correlated Electrons · Physics 2024-12-25 Ya. S. Lyakhova , S. D. Semenov , A. I. Lichtenstein , A. N. Rubtsov

We present a functional interpolation approach within the auxiliary master equation framework to efficiently and accurately solve correlated impurity problems in nonequilibrium dynamical mean-field theory (DMFT). By leveraging a near-exact…

Strongly Correlated Electrons · Physics 2025-06-13 Daniel Werner , Enrico Arrigoni

The accuracy of density-functional theory (DFT) is determined by the quality of the approximate functionals, such as exchange-correlation in electronic DFT and the excess functional in the classical DFT formalism of fluids. The exact…

Non-local magic and anti-flatness provide a measure of the quantum complexity in the wavefunction of a physical system. Supported by entanglement, they cannot be removed by local unitary operations, thus providing basis-independent…

Quantum Physics · Physics 2025-10-28 C. E. P. Robin , M. J. Savage

Two-particle Green's functions and the vertex functions play a critical role in theoretical frameworks for describing strongly correlated electron systems. However, numerical calculations at two-particle level often suffer from large…

Strongly Correlated Electrons · Physics 2018-05-16 Hiroshi Shinaoka , Junya Otsuki , Kristjan Haule , Markus Wallerberger , Emanuel Gull , Kazuyoshi Yoshimi , Masayuki Ohzeki

We show that a lattice formulation of density-functional theory (DFT), guided by renormalization-group concepts, can be used to obtain numerical predictions of energy gaps, spin-density profiles, critical exponents, sound velocities,…

Strongly Correlated Electrons · Physics 2009-11-13 Francisco C. Alcaraz , Klaus Capelle

We investigate a density-functional theory (DFT) approach for an unpolarized trapped dilute Fermi gas in the unitary limit . A reformulation of the recent work of T. Papenbrock [Phys. Rev. A, {\bf 72}, 041602(R) (2005)] in the language of…

Other Condensed Matter · Physics 2009-11-11 Brandon P. van Zyl , D. A. W. Hutchinson , Melodie Need

In this work, we extend the dual triply irreducible local expansion (D-TRILEX) approach for correlated electronic systems by introducing a cluster reference system for the diagrammatic expansion. This framework allows us to consistently…

Strongly Correlated Electrons · Physics 2026-02-26 Félix Fossati , Evgeny A. Stepanov

We generalize the dynamical-mean field (DMFT) approximation by including into the DMFT equations some length scale via a momentum dependent ``external'' self-energy S(k). This external self-energy describes non-local dynamical correlations…

Strongly Correlated Electrons · Physics 2009-11-11 M. V. Sadovskii , I. A. Nekrasov , E. Z. Kuchinskii , Th. Pruschke , V. I. Anisimov

We establish a way to handle main collective fluctuations in correlated quantum systems based on a Fluctuation Local Field concept. This technique goes beyond standard mean-field approaches, such as Hartree-Fock and dynamical mean-field…

Strongly Correlated Electrons · Physics 2021-01-04 Alexey N. Rubtsov , Evgeny A. Stepanov , Alexander I. Lichtenstein

The local volatility model is a widely used for pricing and hedging financial derivatives. While its main appeal is its capability of reproducing any given surface of observed option prices---it provides a perfect fit---the essential…

Computational Finance · Quantitative Finance 2019-01-24 Martin Tegnér , Stephen Roberts

We showcase the advantages of orbital-free density-potential functional theory (DPFT), a more flexible variant of Hohenberg-Kohn density functional theory. DPFT resolves the usual trouble with the gradient-expanded kinetic energy functional…

Quantum Gases · Physics 2021-06-16 Martin-Isbjörn Trappe , Jun Hao Hue , Berthold-Georg Englert

Due to efficient scaling with electron number N, density functional theory (DFT) is widely used for studies of large molecules and solids. Restriction of an exact mean-field theory to local potential functions has recently been questioned.…

Other Condensed Matter · Physics 2015-06-24 Robert K. Nesbet

We develop a method in which the electronic densities of small fragments determined by Kohn-Sham density functional theory (DFT) are embedded using stochastic DFT to form the exact density of the full system. The new method preserves the…

Chemical Physics · Physics 2015-06-19 Daniel Neuhauser , Roi Baer , Eran Rabani

By exploiting the convexity of the two-particle-irreducible (2PI) effective action, we describe a procedure for extracting n-point vertex functions. This procedure is developed within the context of a zero-dimensional "quantum field theory"…

High Energy Physics - Theory · Physics 2022-11-22 Peter Millington , Paul M. Saffin