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Complete active space self-consistent field (CASSCF) computations can be realized at polynomial cost via the variational optimization of the active-space two-electron reduced-density matrix (2-RDM). Like conventional approaches to CASSCF,…

Chemical Physics · Physics 2018-12-10 Mohammad Mostafanejad , A. Eugene DePrince

We discuss an efficient scheme for obtaining spin-polarized quasi-particle excitation energies within the general framework of the density functional theory (DFT). Our approach is to correct the DFT eigenvalues via the electrostatic energy…

Strongly Correlated Electrons · Physics 2007-10-11 B. Barbiellini , A. Bansil

We show that deep neural networks can be integrated into, or fully replace, the Kohn-Sham density functional theory scheme for multi-electron systems in simple harmonic oscillator and random external potentials with no feature engineering.…

Materials Science · Physics 2021-02-25 Kevin Ryczko , David Strubbe , Isaac Tamblyn

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 present a real-space method for computing the random phase approximation (RPA) correlation energy within Kohn-Sham density functional theory, leveraging the low-rank nature of the frequency-dependent density response operator. In…

Computational Physics · Physics 2025-04-03 Boqin Zhang , Shikhar Shah , John E. Pask , Edmond Chow , Phanish Suryanarayana

We are interested in the discretisation of a drift-diffusion system in the framework of hybrid finite volume (HFV) methods on general polygonal/polyhedral meshes. The system under study is composed of two anisotropic and nonlinear…

Numerical Analysis · Mathematics 2023-05-11 Julien Moatti

Approximate functionals used in practical density functional theory (DFT) deviate from the piecewise linear behavior of the exact functional for fractional charges. This deviation causes excess charge delocalization, which leads to…

Chemical Physics · Physics 2018-10-23 Diptarka Hait , Martin Head-Gordon

We study few-shot semantic segmentation that aims to segment a target object from a query image when provided with a few annotated support images of the target class. Several recent methods resort to a feature masking (FM) technique to…

Computer Vision and Pattern Recognition · Computer Science 2022-07-26 Seonghyeon Moon , Samuel S. Sohn , Honglu Zhou , Sejong Yoon , Vladimir Pavlovic , Muhammad Haris Khan , Mubbasir Kapadia

Finite difference method as a popular numerical method has been widely used to solve fractional diffusion equations. In the general spatial error analyses, an assumption $u\in C^{4}(\bar{\Omega})$ is needed to preserve $\mathcal{O}(h^{2})$…

Numerical Analysis · Mathematics 2023-02-07 Daxin Nie , Jing Sun , Weihua Deng

Spin-charge separation (SCS) is a striking manifestation of strong correlations in low-dimensional quantum systems, whereby a fermion splits into separate spin and charge excitations that travel at different speeds. Here, we demonstrate…

Strongly Correlated Electrons · Physics 2020-11-11 Hongmin Gao , Jonathan R. Coulthard , Dieter Jaksch , Jordi Mur-Petit

Efficient time integration schemes are necessary to capture the complex processes involved in atmospheric flows over long periods of time. In this work, we propose a high-order, implicit-explicit numerical scheme that combines Multi-Level…

Numerical Analysis · Mathematics 2018-10-22 Francois Hamon , Martin Schreiber , Michael Minion

We present recent developments of the NTChem program for performing large scale hybrid Density Functional Theory calculations on the supercomputer Fugaku. We combine these developments with our recently proposed Complexity Reduction…

Energy barriers, which control the rates of chemical reactions, are seriously underestimated by computationally-efficient semi-local approximations for the exchange-correlation energy. The accuracy of a semi-local density functional…

Chemical Physics · Physics 2023-11-06 Bikash Kanungo , Aaron D. Kaplan , Chandra Shahi , Vikram Gavini , John P. Perdew

We present a perturbative approach within the scope of Kohn-Sham density functional theory (DFT). The method is based on the exact exchange-only optimized effective potential method, and correlation is included via perturbation expansion…

Chemical Physics · Physics 2007-05-23 P. Sule

The random phase approximation (RPA) for the electron correlation energy, combined with the exact-exchange energy, represents the state-of-the-art exchange-correlation functional within density-functional theory (DFT). However, the standard…

Other Condensed Matter · Physics 2015-05-20 Xinguo Ren , Patrick Rinke , Alexandre Tkatchenko , Matthias Scheffler

Electronic coupling matrix elements are important to the theoretical description of electron transfer processes. However, they are notoriously difficult to obtain accurately from time- dependent density functional theory (TDDFT). Here, we…

Chemical Physics · Physics 2018-12-07 Debashree Manna , Jochen Blumberger , Jan M. L. Martin , Leeor Kronik

Kohn-Sham spin-density functional theory provides an efficient and accurate model to study electron-electron interaction effects in quantum dots, but its application to large systems is a challenge. An efficient algorithm for the…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Hong Jiang , Harold U. Baranger , Weitao Yang

We devise a scheme for converting an existing exchange functional into its range-separated hybrid variant. The underlying exchange hole of the Becke-Roussel type has the exact second-order expansion in the interelectron distance. The…

Chemical Physics · Physics 2016-09-19 Marcin Modrzejewski , Michal Hapka , Grzegorz Chalasinski , Malgorzata M. Szczesniak

We present an algorithm and implementation of integral-direct, density-fitted Hartree-Fock (HF) and second-order M{\o}ller-Plesset perturbation theory (MP2) for periodic systems. The new code eliminates the formerly prohibitive storage…

Chemical Physics · Physics 2022-10-11 Sylvia J. Bintrim , Timothy C. Berkelbach , Hong-Zhou Ye

The magnetic ground state of FeRh is highly sensitive towards the lattice constant. This, in addition to partially filled d-shells of Fe and Rh, posed a significant challenge for Density Functional Theory (DFT) calculations in the past.…

Materials Science · Physics 2024-01-24 Shishir Kumar Pandey , Saikat Debnath , Zhanghao Zhouyina , Qiangqiang Gu