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In comparison with the accurate data on the on-top electron density n(0) in the proton-embedded electron gas with the density parameter r_s in the range 1-12 obtained by diffusion Monte Carlo (DMC) simulations, we have successfully…

Materials Science · Physics 2018-07-18 Yasutami Takada

For translationally invariant one-band lattice models, we exploit the ab initio knowledge of the natural orbitals to simplify reduced density matrix functional theory (RDMFT). Striking underlying features are discovered: First, within each…

Quantum Physics · Physics 2019-01-08 Christian Schilling , Rolf Schilling

While in principle exact, Kohn-Sham density functional theory -- the workhorse of computational chemistry -- must rely on approximations for the exchange-correlation functional. Despite staggering successes, present-day approximations still…

Most density functionals have been developed by imposing the known exact constraints on the exchange-correlation energy, or by a fit to a set of properties of selected systems, or by both. However, accurate modeling of the conventional…

Materials Science · Physics 2016-08-24 Jianmin Tao , Yuxiang Mo

We derive the exchange-correlation potential corresponding to the nonlocal van der Waals density functional [M. Dion, H. Rydberg, E. Schroder, D. C. Langreth, and B. I. Lundqvist, Phys. Rev. Lett. 92, 246401 (2004)]. We use this potential…

Materials Science · Physics 2011-11-09 T. Thonhauser , Valentino R. Cooper , Shen Li , Aaron Puzder , Per Hyldgaard , David C. Langreth

The numerical implementation of an exchange-correlation functional is not always an accurate reproduction of its theoretical specification. For example, density functionals for exchange and correlation can be defined by an exchange or…

Materials Science · Physics 2012-11-01 Jonathan E. Moussa , Peter A. Schultz

Physically valid and numerically efficient approximations for the exchange and correlation energy are critical for reduced density-matrix functional theory to become a widely used method in electronic structure calculations. Here we examine…

Strongly Correlated Electrons · Physics 2016-03-23 A. Putaja , F. G. Eich , T. Baldsiefen , E. Rasanen

The construction of density-functional approximations is explored by modeling the adiabatic connection em locally, using energy densities defined in terms of the electrostatic potential of the exchange-correlation hole. These local models…

Chemical Physics · Physics 2016-05-04 Stefan Vuckovic , Tom Irons , Andreas Savin , Andrew M. Teale , Paola Gori-Giorgi

From a simplified version of the mathematical structure of the strong coupling limit of the exact exchange-correlation functional, we construct an approximation for the electronic repulsion energy at physical coupling strength, which is…

Chemical Physics · Physics 2017-05-11 Stefan Vuckovic , Paola Gori-Giorgi

An alternative type of approximation for the exchange and correlation functional in density functional theory is proposed. This approximation depends on a variable $u$ that is able to detect inhomogeneities in the electron density $\rho$…

Materials Science · Physics 2019-01-02 Fabien Tran , Peter Blaha

We present here novel insight into exchange-correlation functionals in density functional theory, based on the viewpoint of optimal transport. We show that in the case of two electrons and in the semiclassical limit, the exact…

Analysis of PDEs · Mathematics 2015-03-19 Codina Cotar , Gero Friesecke , Claudia Klüppelberg

We present a detailed study of the exchange-correlation hole and exchange-correlation energy per particle in the Si crystal as calculated by the Variational Monte Carlo method and predicted by various density functional models. Nonlocal…

Materials Science · Physics 2009-11-07 A. C. Cancio , M. Y. Chou , Randolph Q. Hood

Most approximate exchange-correlation functionals used within density functional theory are constructed as the sum of two distinct contributions for exchange and correlation. Separating the exchange component from the entire functional is…

Condensed Matter · Physics 2009-10-28 Claudia Filippi , C. J. Umrigar , Xavier Gonze

The Coulomb exchange and correlation energy density functionals for electron systems are applied to nuclear systems. It is found that the exchange functionals in the generalized gradient approximation provide agreements with the exact-Fock…

Nuclear Theory · Physics 2019-12-09 Tomoya Naito , Ryosuke Akashi , Gianluca Colò , Haozhao Liang , Xavier Roca-Maza

The exchange-correlation hole density of the infinitely stretched (dissociated) hydrogen molecule can be cast into a closed analytical form by using its exact wave function. This permits to obtain an explicit exchange-correlation energy…

Chemical Physics · Physics 2017-11-16 Eduard Matito , David Casanova , Xabier Lopez , Jesus M. Ugalde

Long-range exchange and correlation effects, responsible for the failure of currently used approximate density functionals in describing van der Waals forces, are taken into account explicitly after a separation of the electron-electron…

Materials Science · Physics 2009-11-11 Janos G. Angyan , Iann C. Gerber , Andreas Savin , Julien Toulouse

The central quantity of density functional theory is the so-called exchange-correlation functional. This quantity encompasses all non-trivial many-body effects of the ground-state and has to be approximated in any practical application of…

Materials Science · Physics 2012-06-29 Miguel A. L. Marques , Micael J. T. Oliveira , Tobias Burnus

Lieb and Oxford (1981) derived rigorous lower bounds, in the form of local functionals of the electron density, on the indirect part of the Coulomb repulsion energy. The greatest lower bound for a given electron number N depends…

Applied Physics · Physics 2022-06-22 John P. Perdew , Jianwei Sun

In this work we have studied a new functional for the correlation energy obtained from the exact-exchange (EXX) approximation within time-dependent density functional theory (TDDFT). Correlation energies have been calculated for a number of…

Mesoscale and Nanoscale Physics · Physics 2015-05-14 Maria Hellgren , Ulf von Barth

We investigate numerically the model proposed in Sahoo et al [Phys. Rev. Lett. 118, 164501, (2017)] where a parameter $\lambda$ is introduced in the Navier-Stokes equations such that the weight of homochiral to heterochiral interactions is…

Fluid Dynamics · Physics 2022-04-06 Alexandros Alexakis , Luca Biferale