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In this work we investigate Wigner localization at very low densities by means of the exact diagonalization of the Hamiltonian. This yields numerically exact results. In particular, we study a quasi-one-dimensional system of two electrons…

In the distributed nucleus approximation we represent the singular nucleus as smeared over a smallportion of a Cartesian grid. Delocalizing the nucleus allows us to solve the Poisson equation for theoverall electrostatic potential using a…

chem-ph · Physics 2009-10-28 Karthik A. Iyer , Michael P. Merrick , Thomas L. Beck

In this paper, we propose and analyze a second order accurate (in both time and space) numerical scheme for the Poisson-Nernst-Planck-Navier-Stokes system, which describes the ion electro-diffusion in fluids. In particular, the…

Numerical Analysis · Mathematics 2025-03-12 Yuzhe Qin , Cheng Wang

A robust algorithm for non-negative matrix factorization (NMF) is presented in this paper with the purpose of dealing with large-scale data, where the separability assumption is satisfied. In particular, we modify the Linear Programming…

Machine Learning · Statistics 2014-01-10 Jason Gejie Liu , Shuchin Aeron

This paper considers the iterative solution of linear systems arising from discretization of the anisotropic radiative transfer equation with discontinuous elements on the sphere. In order to achieve robust convergence behavior in the…

Numerical Analysis · Mathematics 2021-03-11 Jürgen Dölz , Olena Palii , Matthias Schlottbom

We present a detailed analysis of the spin models with near-neighbors interactions constructed in our previous paper [Phys. Lett. B 605 (2005) 214] by a suitable generalization of the exchange operator formalism. We provide a complete…

Exactly Solvable and Integrable Systems · Physics 2008-11-26 A. Enciso , F. Finkel , A. Gonzalez-Lopez , M. A. Rodriguez

The thorough treatment of electron-lattice interactions from first principles is one of the main goals in condensed matter physics. While the commonly applied adiabatic Born-Oppenheimer approximation is sufficient for describing many…

We consider a direct optimization approach for ensemble density functional theory electronic structure calculations. The update operator for the electronic orbitals takes the structure of the Stiefel manifold into account and we present an…

Computational Physics · Physics 2012-07-11 K. Baarman , V. Havu , T. Eirola

We develop relativistic short-range exchange energy functionals for four-component relativistic range-separated density-functional theory using a Dirac-Coulomb Hamiltonian in the no-pair approximation. We show how to improve the short-range…

Chemical Physics · Physics 2020-06-24 Julien Paquier , Emmanuel Giner , Julien Toulouse

We propose a simple and effective method for designing approximation formulas for weighted analytic functions. We consider spaces of such functions according to weight functions expressing the decay properties of the functions. Then, we…

Numerical Analysis · Mathematics 2018-08-31 Ken'ichiro Tanaka , Masaaki Sugihara

Plane-wave electronic-structure predictions based upon orbital-dependent density-functional theory (OD-DFT) approximations, such as hybrid density-functional methods and self-interaction density-functional corrections, are severely affected…

Materials Science · Physics 2011-10-19 Yanli Li , Ismaila Dabo

In this paper, we develop two fast implicit difference schemes for solving a class of variable-coefficient time-space fractional diffusion equations with integral fractional Laplacian (IFL). The proposed schemes utilize the graded $L1$…

Numerical Analysis · Mathematics 2021-07-26 Xian-Ming Gu , Hai-Wei Sun , Yanzhi Zhang , Yong-Liang Zhao

We propose an efficient algorithmic framework for time domain circuit simulation using exponential integrator. This work addresses several critical issues exposed by previous matrix exponential based circuit simulation research, and makes…

Computational Engineering, Finance, and Science · Computer Science 2016-11-17 Hao Zhuang , Wenjian Yu , Ilgweon Kang , Xinan Wang , Chung-Kuan Cheng

For translationally invariant one-band lattice models, we exploit the ab initio knowledge of the natural orbitals to simplify reduced density matrix functional theory (RDMFT). Striking underlying features are discovered: First, within each…

Quantum Physics · Physics 2019-01-08 Christian Schilling , Rolf Schilling

Neutrino mass constraints are a primary focus of current and future large-scale structure (LSS) surveys. Non-linear LSS models rely heavily on cosmological simulations -- the impact of massive neutrinos should therefore be included in these…

Cosmology and Nongalactic Astrophysics · Physics 2024-06-11 James M. Sullivan , J. D. Emberson , Salman Habib , Nicholas Frontiere

We present a quantum algorithm for the simulation of molecular systems that is asymptotically more efficient than all previous algorithms in the literature in terms of the main problem parameters. As in previous work [Babbush et al., New…

The dynamics of cross-diffusion models leads to a high computational complexity for implicit difference schemes, turning them unsuitable for tasks that require results in real-time. We propose the use of two operator splitting schemes for…

Numerical Analysis · Mathematics 2022-02-24 Diogo Lobo

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…

In many recent applications when new materials and technologies are developed it is important to describe and simulate new nonlinear and nonlocal diffusion transport processes. A general class of such models deals with nonlocal fractional…

Numerical Analysis · Mathematics 2024-12-20 Raimondas Ciegis , Petr Vabishchevich

Exact-exchange energy density and energy density of a semilocal density functional approximation are two key ingredients for modeling the static correlation, a strongly nonlocal functional of the density, through a local hybrid functional.…

Materials Science · Physics 2009-11-13 Jianmin Tao , Viktor N. Staroverov , Gustavo E. Scuseria , John P. Perdew