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Classical compressed sensing (CS) allows us to recover structured signals from far few linear measurements than traditionally prescribed, thereby efficiently decreasing sampling rates. However, if there exist nonlinearities in the…

Information Theory · Computer Science 2015-06-09 Jiawang Yi , Guanzheng Tan

We derive a non-perturbative, closed, analytic equation for the non-linear power spectrum of cosmic density fluctuations. This result is based on our kinetic field theory (KFT) of cosmic structure formation and on evaluating particle…

Cosmology and Nongalactic Astrophysics · Physics 2017-10-23 Matthias Bartelmann , Felix Fabis , Sara Konrad , Elena Kozlikin , Robert Lilow , Carsten Littek , Johannes Dombrowski

We present enhancements to the computational efficiency of exact exchange calculations using the density matrix and local support functions. We introduce a numerical method which avoids the explicit calculation the four-center two-electron…

Chemical Physics · Physics 2016-11-25 Lionel A. Truflandier , Tsuyoshi Miyazaki , David R. Bowler

In the paper, we consider the line spectral estimation problem in an unlimited sensing framework (USF), where a modulo analog-to-digital converter (ADC) is employed to fold the input signal back into a bounded interval before quantization.…

Signal Processing · Electrical Eng. & Systems 2024-08-14 Hongwei Wang , Jun Fang , Hongbin Li , Geert Leus

Approximating functions by a linear span of truncated basis sets is a standard procedure for the numerical solution of differential and integral equations. Commonly used concepts of approximation methods are well-posed and convergent, by…

Numerical Analysis · Mathematics 2022-12-14 Yahya Saleh , Armin Iske , Andrey Yachmenev , Jochen Küpper

The Fock expansion, which describes the properties of two-electron atoms near the nucleus, is studied. The angular Fock coefficients $\psi_{k,p}(\alpha,\theta)$ with the maximum possible value of subscript $p$ are calculated on examples of…

Atomic Physics · Physics 2022-10-14 Evgeny Z. Liverts , Rajmund Krivec

A linear-scaling algorithm is presented for computing the Hartree-Fock (HF) exchange matrix using concentric atomic density fitting. The algorithm utilizes the stronger distance dependence of the three-center electron repulsion integrals…

Chemical Physics · Physics 2014-10-21 David S. Hollman , Henry F. Schaefer , Edward F. Valeev

We present in this article an analysis of some of the properties of the density field realized in numerical simulations for power-law initial power-spectra in the case of a critical density universe. We compare our numerical results in the…

Astrophysics · Physics 2009-10-31 P. Valageas , C. Lacey , R. Schaeffer

We construct a coalescence hidden variable fractal interpolation function (CHFIF) through a non-diagonal iterated function system(IFS). Such a FIF may be self-affine or non-self-affine depending on the parameters of the defining…

Dynamical Systems · Mathematics 2007-05-23 A. K. B. Chand , G. P. Kapoor

A general procedure for the optimization of atomic density-fitting basis functions is designed with the balance between accuracy and numerical stability in mind. Given one-electron wavefunctions and energies, weights are assigned to the…

Chemical Physics · Physics 2020-10-13 Dimitri N. Laikov

The layering approach used in fused filament fabrication (FFF) enables creation of complex designs generated by topology optimization. Defects associated with the layer-by-layer process, introduce considerable random variability to the…

Materials Science · Physics 2024-09-04 Zahra Kazemi , Craig A. Steeves

The exact values of the presently determined components 26of the angular Fock coefficients at the two-particle coalescences were obtained and systematized. The Green Function approach was successfully applied to simplify the most…

Atomic Physics · Physics 2016-08-24 Evgeny Z. Liverts

Most statistical inference from cosmic large-scale structure relies on two-point statistics, i.e.\ on the galaxy-galaxy correlation function (2PCF) or the power spectrum. These statistics capture the full information encoded in the Fourier…

Cosmology and Nongalactic Astrophysics · Physics 2023-06-09 Kamran Ali , Danail Obreschkow , Cullan Howlett , Camille Bonvin , Claudio Llinares , Felipe Oliveira Franco , Chris Power

Noncollinear (NC) magnetism and spin-orbit coupling (SOC) are indispensable for predictive ab initio materials simulations with pronounced relativistic effects and magnetic frustration, yet they significantly increase the cost of…

The concept of localization in Fock space is extended to the study of the many particle excitation statistics of interacting electrons in a two dimensional quantum dot. In addition, a finite size scaling hypothesis for Fock space…

Mesoscale and Nanoscale Physics · Physics 2009-10-30 R. Berkovits , Y. Avishai

Feature preprocessing continues to play a critical role when applying machine learning and statistical methods to tabular data. In this paper, we propose the use of the kernel density integral transformation as a feature preprocessing step.…

Machine Learning · Statistics 2023-10-20 Calvin McCarter

We demonstrate that measurements of number fluctuations within finite cells provide a direct means to study fluctuation scaling in a trapped two-component condensate. This quantum system supports a second-order phase transition between…

Quantum Gases · Physics 2015-05-19 R. N. Bisset , R. M. Wilson , C. Ticknor

Nonlinear subspace clustering based on a feed-forward neural network has been demonstrated to provide better clustering accuracy than some advanced subspace clustering algorithms. While this approach demonstrates impressive outcomes, it…

Machine Learning · Computer Science 2024-08-28 Long Shi , Lei Cao , Zhongpu Chen , Badong Chen , Yu Zhao

The relaxed and unrelaxed formation energies of neutral antisites and interstitial defects in InP are calculated using ab initio density functional theory and simple cubic supercells of up to 512 atoms. The finite size errors in the…

Other Condensed Matter · Physics 2009-11-11 C. W. M. Castleton , S. Mirbt

In this contribution, we present the implementation of a second-order CASSCF algorithm in conjunction with the Cholesky decomposition of the two-electron repulsion integrals. The algorithm, called Norm-Extended Optimization, guarantees…

Chemical Physics · Physics 2021-04-09 Tommaso Nottoli , Jürgen Gauss , Filippo Lipparini