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Related papers: 1D Kinetic Energy Density Functionals learned with…

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We visualize the Kohn-Sham kinetic energy density (KED), and the ingredients -- the electron density, its gradient and Laplacian -- used to construct orbital-free models of it, for the AE6 test set of molecules. These are compared to…

Chemical Physics · Physics 2016-03-01 Antonio C. Cancio , Dane Stewart , Aeryk I. Kuna

We report a local, weight-dependent correlation density-functional approximation that incorporates information about both ground and excited states in the context of density-functional theory for ensembles (eDFT). This density-functional…

Chemical Physics · Physics 2020-06-05 Pierre-François Loos , Emmanuel Fromager

Functionals that strive to correct for such self-interaction errors, such as those obtained by imposing the Perdew-Zunger self-interaction correction or the generalized Koopmans' condition, become orbital dependent or orbital-density…

Materials Science · Physics 2011-08-30 Cheol-Hwan Park , Andrea Ferretti , Ismaila Dabo , Nicolas Poilvert , Nicola Marzari

We review an approach where the energy functional of Density-Functional Theory (DFT) can be determined without empiricism via a Quantum Monte Carlo (QMC) procedure. The idea consists of a nested iterative loop where the configurational…

Strongly Correlated Electrons · Physics 2017-11-22 Luigi Delle Site

Orbital-free density functional theory (OF-DFT) for real-space systems has historically depended on Lagrange optimization techniques, primarily due to the inability of previously proposed electron density approaches to ensure the…

Chemical Physics · Physics 2024-11-08 Alexandre de Camargo , Ricky T. Q. Chen , Rodrigo A. Vargas-Hernández

A direct orbital optimization method is presented for density functional calculations of excited electronic states using either a real space grid or a plane wave basis set. The method is variational, provides atomic forces in the excited…

Computational Physics · Physics 2022-11-09 Aleksei V. Ivanov , Gianluca Levi , Elvar Ö. Jónsson , Hannes Jónsson

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

Orbital-free Density Functional Theory (OF-DFT) has been used when studying atoms, molecules and solids. In nuclear physics, there has been basically no application of OF-DFT so far, as the Density Functional Theory (DFT) has been widely…

Nuclear Theory · Physics 2023-08-03 Gianluca Colo' , Kouichi Hagino

The electron density of a molecule or material has recently received major attention as a target quantity of machine-learning models. A natural choice to construct a model that yields transferable and linear-scaling predictions is to…

Chemical Physics · Physics 2022-06-29 Andrea Grisafi , Alan M. Lewis , Mariana Rossi , Michele Ceriotti

We present a Gaussian-basis implementation of orbital-free density-functional theory (OF-DFT) in which the trust-region image method (TRIM) is used for optimization. This second-order optimization scheme has been constructed to provide…

Chemical Physics · Physics 2021-09-15 Matthew S. Ryley , Michael Withnall , Tom J. P. Irons , Trygve Helgaker , Andrew M. Teale

Most realistic calculations of moderately correlated materials begin with a ground-state density functional theory (DFT) calculation. While Kohn-Sham DFT is used in about 40,000 scientific papers each year, the fundamental underpinnings are…

Strongly Correlated Electrons · Physics 2022-09-26 Kieron Burke , John Kozlowski

The self consistent version of the density functional theory (DFT) is presented, which allows to calculate the ground state and dynamic properties of finite multi-electron systems such as atoms, molecules and clusters. The exact functional…

Condensed Matter · Physics 2007-05-23 M. Ya. Amusia , V. R. Shaginyan

Kernel ridge regression is used to approximate the kinetic energy of non-interacting fermions in a one-dimensional box as a functional of their density. The properties of different kernels and methods of cross-validation are explored, and…

In the current density functional theory of linear and nonlinear time-dependent phenomena, the treatment of exchange and correlation beyond the level of the adiabatic local density approximation is shown to lead to the appearance of…

Condensed Matter · Physics 2009-10-30 G. Vignale , C. A. Ullrich , S. Conti

Electrons in zero external magnetic field can be studied with density functional theory (DFT) or with spin-DFT (SDFT). The latter is normally used for open shell systems because its approximations appear to model better the exchange and…

Chemical Physics · Physics 2022-04-06 Timothy Callow , Benjamin Pearce , Nikitas Gidopoulos

Density Functional Theory (DFT) is one of the most widely used methods for "ab initio" calculations of the structure of atoms, molecules, crystals, surfaces, and their interactions. Unfortunately, the customary introduction to DFT is often…

Physics Education · Physics 2010-12-07 Nathan Argaman , Guy Makov

A system of electrons in a local or nonlocal external potential can be studied with 1-matrix functional theory (1MFT), which is similar to density functional theory (DFT) but takes the one-particle reduced density matrix (1-matrix) instead…

Strongly Correlated Electrons · Physics 2008-07-23 Ryan Requist , Oleg Pankratov

This paper gives an introduction to the Keldysh formalism, with emphasis on its usefulness in time-dependent density functional theory. In the first part we introduce the Keldysh contour and the one-particle Green function defined on this…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Robert van Leeuwen , Nils Erik Dahlen , Gianluca Stefanucci , Carl-Olof Almbladh , Ulf von Barth

Computational fluid dynamics (CFD) analysis is widely used in engineering. Although CFD calculations are accurate, the computational cost associated with complex systems makes it difficult to obtain empirical equations between system…

Fluid Dynamics · Physics 2022-04-08 Mehrad Ansari , Heta A. Gandhi , David G. Foster , Andrew D. White

We develop an ensemble density functional theory for the fractional quantum Hall effect using a local density approximation. Model calculations for edge reconstructions of a spin-polarized quantum dot give results in good agreement with…

Condensed Matter · Physics 2009-10-28 O. Heinonen , M. I. Lubin , M. D. Johnson