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Density Functional Theory (DFT) is widely used for atomistic simulations. However, its reach stays limited due to several limitations such as lack of accurate exchange-correlation functional, requirement of costly O(N 3) diagonalization…

Quantum Physics · Physics 2026-05-18 Namrata Manglani , Samrit Kumar Maity , Shashank Sharma , Soham Phulare , Sanjay Wandhekar

In the present work, we employ exact diagonalization for model systems on a real-space lattice to explicitly construct the exact density-to-potential and for the first time the exact density-to-wavefunction map that underly the…

Chemical Physics · Physics 2016-08-24 Tanja Dimitrov , Heiko Appel , Johanna I. Fuks , Angel Rubio

Density functional theory can be extended to excited states by means of a unified variational approach for passive state ensembles. This extension overcomes the restriction of the typical density functional approach to ground states, and…

Chemical Physics · Physics 2019-07-10 Tim Gould , Stefano Pittalis

We develop a new general algorithm for finding a regular tight-binding lattice Hamiltonian in infinite dimensions for an arbitrary given shape of the density of states (DOS). The availability of such an algorithm is essential for the…

Strongly Correlated Electrons · Physics 2007-05-23 N. Blümer , P. G. J. van Dongen

We benchmark the ground state energies and the density profiles of atomic repulsive Fermi gases in optical lattices computed via Density Functional Theory (DFT) against the results of diffusion Monte Carlo (DMC) simulations. The main focus…

Quantum Gases · Physics 2018-06-12 S. Pilati , I. Zintchenko , M. Troyer , F. Ancilotto

By combining methods of kinetic and density functional theory, we present a description of molecular fluids which accounts for their microscopic structure and thermodynamic properties as well as for the hydrodynamic behavior. We focus on…

Mesoscale and Nanoscale Physics · Physics 2015-05-18 Umberto Marini Bettolo Marconi , Simone Melchionna

Density-functional theory is applied to compute the ground-state energies of quantum hard-sphere solids. The modified weighted-density approximation is used to map both the Bose and the Fermi solid onto a corresponding uniform Bose liquid,…

Statistical Mechanics · Physics 2009-10-30 A. R. Denton , P. Nielaba , N. W. Ashcroft

A density functional theory (DFT) of lattice fermion models is presented, which uses the single-particle density matrix gamma_{ij} as basic variable. A simple, explicit approximation to the interaction-energy functional W[gamma] of the…

Strongly Correlated Electrons · Physics 2009-11-07 R. Lopez-Sandoval , G. M. Pastor

Over the past two decades, many studies in the Density Functional Theory context revealed new aspects and properties of strongly correlated superfluid quantum systems in numerous configurations that can be simulated in experiments. This was…

Quantum Gases · Physics 2022-07-08 Antoine Boulet , Gabriel Wlazłowski , Piotr Magierski

A detailed analysis of density-functional theory for quantum-electrodynamical model systems is provided. In particular, the quantum Rabi model, the Dicke model, and a generalization of the latter to multiple modes are considered. We prove a…

Mathematical Physics · Physics 2025-04-24 Vebjørn H. Bakkestuen , Mihály A. Csirik , Andre Laestadius , Markus Penz

We present an extension of the density-functional theory (DFT) formalism for lattice gases to systems with internal degrees of freedom. In order to test approximations commonly used in DFT approaches, we investigate the statics and dynamics…

Statistical Mechanics · Physics 2009-11-10 S. Heinrichs , W. Dieterich , P. Maass , H. L. Frisch

As density functional theory conventionally assumes that the density of a chosen model system (e.g., the Kohn-Sham system) is the same as the exact one, one might expect that approximations to the exact density introduce supplementary…

Chemical Physics · Physics 2009-02-17 A. Savin

Static electric response properties of atoms and molecules are reported within the real-space Cartesian grid implementation of pseudopotential Kohn-Sham (KS) density functional theory (DFT). A detailed systematic investigation is made for a…

Chemical Physics · Physics 2019-04-26 Tanmay Mandal , Abhisek Ghosal , Amlan K. Roy

Quantum dots with conduction electrons or holes originating from several bands are considered. We assume the particles are confined in a harmonic potential and assume the electrons (or holes) belonging to different bands to be different…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 K. Karkkainen M. Koskinen , S. M. Reimann , M. Manninen

For the kinetic energy of 1d model finite systems the leading corrections to local approximations as a functional of the potential are derived using semiclassical methods. The corrections are simple, non-local functionals of the potential.…

Other Condensed Matter · Physics 2010-06-25 Attila Cangi , Donghyung Lee , Peter Elliott , Kieron Burke

The extension of the density functional theory (DFT) to include pairing correlations without formal violation of the particle-number conservation condition is described. This version of the theory can be considered as a foundation of the…

Nuclear Theory · Physics 2007-05-23 S. Krewald , V. B. Soubbotin , V. I. Tselyaev , X. Vinas

A critical challenge for density functional theory (DFT) in practice is its limited ability to treat static electron correlation, leading to errors in its prediction of charges, multiradicals, and reaction barriers. Recently, we combined…

Chemical Physics · Physics 2024-11-05 Daniel Gibney , Jan-Niklas Boyn , David A. Mazziotti

Time-dependent density functional theory, proposed recently in the context of atomic diffusion and non-equilibrium processes in solids, is tested against Monte Carlo simulation. In order to assess the basic approximation of that theory, the…

Statistical Mechanics · Physics 2009-11-07 M. Kessler , W. Dieterich , H. L. Frisch , J. F. Gouyet , P. Maass

A generalization of the Density Functional Theory is proposed. The theory developed leads to single-particle equations of motion with a quasi-local mean-field operator, which contains a quasi-particle position-dependent effective mass and a…

Nuclear Theory · Physics 2009-11-07 V. B. Soubbotin , V. I. Tselyaev , X. Vinas

Nanoscale optoelectronics and molecular-electronics systems operate with current injection and nonequilibrium tunneling, phenomena that challenge consistent descriptions of the steady-state transport. The current affects the…

Other Condensed Matter · Physics 2009-11-13 Per Hyldgaard