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Accurate exchange-correlation (XC) potentials for 3-dimensional systems -- via solution of the \emph{inverse} density functional theory (DFT) problem -- are now available to test the quality of DFT approximations. Herein, the \emph{exact}…

Chemical Physics · Physics 2021-11-18 Bikash Kanungo , Paul M. Zimmerman , Vikram Gavini

Hund's pairing refers to Cooper pairing generated by onsite interactions that become attractive due to large Hund's exchange $J$. This is possible in multiorbital systems even when all local bare interactions are repulsive, since attraction…

Superconductivity · Physics 2022-09-13 Mercè Roig , Astrid T. Rømer , Andreas Kreisel , P. J. Hirschfeld , Brian M. Andersen

Coupled elliptic quantum dots with different aspect ratios containing up to two electrons are studied using a model confinement potential in the presence of magnetic fields. Single and two particle Schroedinger equations are solved using…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 L. -X. Zhang , D. V. Melnikov , J. -P. Leburton

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

We obtain the effective action of tunnel-coupled quantum dots, by modeling the system as a Luttinger liquid with multiple barriers. For a double dot system, we find that the resonance conditions for perfect conductance form a hexagon in the…

Mesoscale and Nanoscale Physics · Physics 2007-12-03 Sourin Das , Sumathi Rao

In density functional theory (DFT), exact constraints, fundamental mathematical properties of the exchange-correlation (XC) energy and its underlying XC hole, along with paradigm systems such as the uniform electron gas and the hydrogen…

Materials Science · Physics 2026-03-13 Yan Oueis , Akilan Ramasamy , James W. Furness , Jamin Kidd , Timo Lebeda , Jianwei Sun

A practical electronic structure method in which a two-body functional is the fundamental variable is constructed. The basic formalism of our method is equivalent to Hartree-Fock density matrix functional theory [M. Levy in {\it Density…

Other Condensed Matter · Physics 2008-04-23 Balazs Hetenyi , Andreas W. Hauser

Orbital modeling of two electron spins confined in a double quantum dot is revisited. We develop an extended Hund Mulliken approach that includes excited orbitals, allowing for a triplet configuration with both electrons residing in a…

Mesoscale and Nanoscale Physics · Physics 2018-01-31 Zack White , Guy Ramon

A framework for developing new approximate electronic structure methods is presented, in which the correlation energy of a many-electron system in the ground state is computed as in the single-reference second-order many-body perturbation…

Chemical Physics · Physics 2011-06-15 Dimitri Laikov

While the exact total energy of a separated open system varies linearly as a function of average electron number between adjacent integers, the energy predicted by semi-local density functional approximations curves upward and the…

We show that the spin-and-space unrestricted Hartree-Fock method, in conjunction with the companion step of the restoration of spin and space symmetries via Projection Techniques (when such symmetries are broken), is able to describe the…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 Constantine Yannouleas , Uzi Landman

The dynamical, long-wavelength longitudinal and transverse exchange-correlation potentials for a homogeneous electron gas are evaluated in a microscopic model based on an approximate decoupling of the equation of motion for the…

Condensed Matter · Physics 2009-10-30 S. Conti , R. Nifosi' , M P Tosi

We present a practical and accurate density functional for the exchange-correlation energy of electrons in two dimensions. The exchange part is based on a recent two-dimensional generalized-gradient approximation derived by considering the…

Strongly Correlated Electrons · Physics 2010-06-30 E. Rasanen , S. Pittalis , J. G. Vilhena , M. A. L. Marques

This work presents exchange potentials for specific orbitals calculated by inverting Hartree-Fock wavefunctions. This was achieved by using a Depurated Inversion Method. The basic idea of the method relies upon the substitution of…

Atomic and Molecular Clusters · Physics 2016-10-21 A. M. P. Mendez , D. M. Mitnik , J. E. Miraglia

We consider density functionals for exchange and correlation energies in two-dimensional systems. The functionals are constructed by making use of exact constraints for the angular averages of the corresponding exchange and correlation…

Strongly Correlated Electrons · Physics 2010-02-25 E. Rasanen , S. Pittalis

Multiorbital interactions have the capacity to produce an interesting kind of doublon-holon bound state that consists of a single-hole state in one band and a doubly-occupied state in another band. Interband doublon-holon pair excitations…

Strongly Correlated Electrons · Physics 2019-09-04 Yuekun Niu , Jian Sun , Yu Ni , Jingyi Liu , Yun Song , Shiping Feng

A detailed convex analysis-based formulation of density-functional theory for periodic systems in arbitrary dimensions is presented. The electron-electron interaction is taken to be of Yukawa type, harmonising with underlying function…

Chemical Physics · Physics 2026-02-23 Oliver M. Bohle , Maryam Lotfigolian , Andre Laestadius , Erik I. Tellgren

A method for calculating the Kohn--Sham exchange-correlation potential, $v_\text{XC}(\mathbf{r})$, from a given electronic wavefunction is devised and implemented. It requires on input one- and two-electron density matrices and involves…

Chemical Physics · Physics 2015-08-19 Ilya G. Ryabinkin , Sviataslau V. Kohut , Viktor N. Staroverov

Following a recent work [Gal, Phys. Rev. A 64, 062503 (2001)], a simple derivation of the density-functional correction of the Hartree-Fock equations, the Hartree-Fock-Kohn-Sham equations, is presented, completing an integrated view of…

Chemical Physics · Physics 2008-09-11 Tamas Gal

Several prominent proposals have suggested that spins of localized electrons could serve as quantum computer qubits. The exchange interaction has been invoked as a means of implementing two qubit gates. In this paper, we analyze the…

Strongly Correlated Electrons · Physics 2016-08-31 Ari Mizel , Daniel A. Lidar