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Like single perovskites, halide double perovskites (HDP) have truly emerged as efficient optoelectronic materials since they display superior stability and are free of toxicity. However, challenges still exist due to either wide and…

Materials Science · Physics 2023-09-13 Mayank Gupta , Susmita Jana , B. R. K. Nanda

We propose global hybrid approximations of the exchange-correlation (XC) energy functional which reproduce well the modified fourth-order gradient expansion of the exchange energy in the semiclassical limit of many-electron neutral atoms…

Chemical Physics · Physics 2015-01-22 E. Fabiano , L. A. Constantin , P. Cortona , F. Della Sala

The fundamental measure approach to classical density functional theory has been shown to be a powerful tool to predict various thermodynamic properties of hard-sphere systems. We employ this approach to determine not only one-particle…

Soft Condensed Matter · Physics 2015-11-02 Andreas Härtel , Matthias Kohl , Michael Schmiedeberg

Based on the Schrodinger equation, exact expressions for the non-relativistic particle energy in the local external field and the external field potential are derived as inhomogeneous density functionals. On this basis, it is shown that,…

Statistical Mechanics · Physics 2011-03-24 V. B. Bobrov , S. A. Trigger

A new reference state for density functional theory, termed the independent atom ansatz, is introduced in this work. This ansatz allows for the exact representation of electron density in terms of non-interacting, atom-localized orbitals.…

Chemical Physics · Physics 2024-05-03 Alexander V. Mironenko

The density functional approach in the Kohn-Sham approximation is widely used to study properties of many-electron systems. Due to the nonlinearity of the Kohn-Sham equations, the general self-consistence searching method involves…

Materials Science · Physics 2015-05-13 D. V. Posvyanskii , A. Ya. Shul'man

This chapter presents the development of a density functional theory (DFT)-based method for accurate, reliable treatment of various resonances in atoms. Many of these are known to be notorious for their strong correlation, proximity to more…

Chemical Physics · Physics 2019-04-19 Amlan K. Roy

With the aim of describing real-time electron dynamics, we introduce an adiabatic approximation for the equation of motion of the one-body reduced-density matrix (one-matrix). The eigenvalues of the one-matrix, which represent the…

Strongly Correlated Electrons · Physics 2012-09-18 Ryan Requist , Oleg Pankratov

The Relativistic Hartree-Fock-Bogoliubov model for axially deformed nuclei (RHFBz) is introduced. The model is based on an effective Lagrangian with density-dependent meson-nucleon couplings in the particle-hole channel, and the pairing…

Nuclear Theory · Physics 2011-08-02 J. -P. Ebran , E. Khan , D. Pena Arteaga , D. Vretenar

Condensed Fermi systems with an odd number of particles can be described by means of polarizing external fields having a time-odd character. We illustrate how this works for Fermi gases and atomic nuclei treated by density functional theory…

Superconductivity · Physics 2009-09-20 George Bertsch , Jacek Dobaczewski , Witold Nazarewicz , Junchen Pei

We start from the Bethe-Goldstone equation (BGE) to derive a simple orbital-dependent correlation functional -- BGE2 -- which terminates the BGE expansion at the second-order, but retains the self-consistent coupling of electron-pair…

Materials Science · Physics 2018-10-19 Igor Ying Zhang , Patrick Rinke , Matthias Scheffler

A model to describe electronic correlations in energy bands is considered. The model is a generalization of the conventional Hubbard model that allows for the fact that the wavefunction for two electrons occupying the same Wannier orbital…

Strongly Correlated Electrons · Physics 2009-11-07 J. E. Hirsch

We develop a perturbative model to treat the off-diagonal components in the Hartree-Fock-Bogoliubov (HFB) transformation matrix, which are neglected in the BCS approximation. Applying the perturbative model to a weakly bound nucleus…

Nuclear Theory · Physics 2009-11-10 K. Hagino , H. Sagawa

We benchmark three standard approximations for the many-body problem -- the Hartree-Fock, projected Hartree-Fock, and random phase approximations -- against full numerical configuration-interaction calculations of the electronic structure…

Atomic Physics · Physics 2012-08-31 Micah D. Schuster , Calvin W. Johnson , Joshua T. Staker

Density functional theory (DFT) embedding provides a formally exact framework for interfacing correlated wave-function theory (WFT) methods with lower-level descriptions of electronic structure. Here, we report techniques to improve the…

Chemical Physics · Physics 2015-06-12 Jason D. Goodpaster , Taylor A. Barnes , Frederick R. Manby , Thomas F. Miller

We proposed a distributed approximating functional method for efficiently describing the electronic dynamics in atoms and molecules in the presence of the Coulomb singularities, using the kernel of a grid representation derived by using the…

Computational Physics · Physics 2016-04-05 Zhigang Sun

Density functionals with a range-separated treatment of the exchange energy are known to improve upon their semilocal forerunners and fixed-fraction hybrids. The conversion of a given semilocal functional into its short-range analog is not…

Chemical Physics · Physics 2019-09-09 Dimitri N. Laikov

We describe a procedure for mapping a self-consistent mean-field theory (also known as density functional theory) into a shell model Hamiltonian that includes quadrupole-quadrupole and monopole pairing interactions in a truncated space. We…

Nuclear Theory · Physics 2008-11-26 R. Rodriguez-Guzman , Y. Alhassid , G. F. Bertsch

Based on recent progress on fermionic exchange symmetry we propose a way to develop new functionals for reduced density matrix functional theory. For some settings with an odd number of electrons, by assuming saturation of the inequalities…

Strongly Correlated Electrons · Physics 2018-10-23 Carlos L. Benavides-Riveros , Miguel A. L. Marques

We present an overview of the Hartree-Fock-Bogoliubov (HFB) theory of nucleonic superfluidity for finite nuclei. After introducing basic concepts related to pairing correlations, we show how the correlated pairs are incorporated into the…

Nuclear Theory · Physics 2017-08-23 J. Dobaczewski , W. Nazarewicz