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Para-Hermitian polynomial matrices obtained by matrix spectral factorization lead to functions useful in control theory systems, basis functions in numerical methods or multiscaling functions used in signal processing. We introduce a fast…

Numerical Analysis · Mathematics 2023-12-12 Vasil Kolev , Todor Cooklev , Fritz Keinert

The linearized collision operator of the Boltzmann equation for single species can be written as a sum of a positive multiplication operator, the collision frequency, and a compact integral operator. This classical result has more recently,…

Analysis of PDEs · Mathematics 2023-07-21 Niclas Bernhoff

An exactly solvable many-particle quantum system is proposed by adding some nonhermitian but PT invariant interactions to the $B_N$ Calogero model. We have shown that such extended $B_N$ Calogero model leads to completely real spectrum…

Statistical Mechanics · Physics 2009-11-07 B. Basu-Mallick , Bhabani Prasad Mandal

This article introduces an iterative method for solving nonsingular non-Hermitian positive semidefinite systems of linear equations. To construct the iteration process, the coefficient matrix is split into two non-Hermitian positive…

Numerical Analysis · Mathematics 2025-03-05 Davod Khojasteh Salkuyeh , Mohsen Masoudi

In this study, a novel machine learning algorithm, restricted Boltzmann machine (RBM), is introduced. The algorithm is applied for the spectral classification in astronomy. RBM is a bipartite generative graphical model with two separate…

Machine Learning · Computer Science 2013-10-15 Fuqiang Chen , Yan Wu , Yude Bu , Guodong Zhao

We present a hybrid Boltzmann-BGK model for inert mixtures, where each kind of binary interaction may be described by a classical Boltzmann integral or by a suitable relaxation-type operator. We allow also the possibility of changing the…

Mathematical Physics · Physics 2025-05-27 Marzia Bisi , Maria Groppi , Giorgio Martalò

This work is devoted to the numerical implementation of the quantum Bhatnagar- Gross-Krook (BGK) model for gas mixtures consisting of classical and quantum particles (fermions, bosons). We consider the model proposed by Bae, Klingenberg,…

Numerical Analysis · Mathematics 2025-02-04 Gi-Chan Bae , Marlies Pirner , Sandra Warnecke

An original spectral study of the compressible hybrid lattice Boltzmann method (HLBM) on standard lattice is proposed. In this framework, the mass and momentum equations are addressed using the lattice Boltzmann method (LBM), while finite…

Computational Physics · Physics 2020-06-16 Florian Renard , Gauthier Wissocq , Jean-François Boussuge , Pierre Sagaut

We propose an entropic Fourier method for the numerical discretization of the Boltzmann collision operator. The method, which is obtained by modifying a Fourier Galerkin method to match the form of the discrete velocity method, can be…

Numerical Analysis · Mathematics 2018-07-05 Zhenning Cai , Yuwei Fan , Lexing Ying

To advance hierarchial equations of motion as a standard theory for quantum dissipative dynamics, we put forward a mixed Heisenberg--Schrodinger scheme with block-matrix implementation on efficient evaluation of nonlinear optical response…

Chemical Physics · Physics 2015-05-30 Jian Xu , Rui-Xue Xu , Darius Abramavicius , Houdao Zhang , YiJing Yan

The purpose of this study is to apply some new RBF collocation schemes and recently-developed kernel RBFs to various types of partial differential equation systems. By analogy with the Fasshauer's Hermite interpolation, we recently…

Numerical Analysis · Mathematics 2025-10-20 W. Chen

This paper a kinetic Boltzmann equation having a general type of collision kernel and modelling spin-dependent Fermi gases at low temperatures modelled by a kinetic equation of Boltzmann type. The distribution functions have values in the…

Quantum Gases · Physics 2013-06-18 L. Arkeryd

This work is concerned with spectral collocation methods for fractional PDEs in unbounded domains. The method consists of expanding the solution with proper global basis functions and imposing collocation conditions on the Gauss-Hermite…

Numerical Analysis · Mathematics 2018-01-30 Tao Tang , Huifang Yuan , Tao Zhou

When the molecules of a gaseous system are far apart, say in microscale gas flows where the surface to volume ratio is high and hence the surface forces dominant, the molecule-surface interactions lead to the formation of a local…

Computational Physics · Physics 2019-07-02 Shashank Jaiswal , Jingwei Hu , Julien K. Brillon , Alina A. Alexeenko

We develop a latent variable model and an efficient spectral algorithm motivated by the recent emergence of very large data sets of chromatin marks from multiple human cell types. A natural model for chromatin data in one cell type is a…

Machine Learning · Statistics 2015-06-09 Chicheng Zhang , Jimin Song , Kevin C Chen , Kamalika Chaudhuri

The precise description of quantum nuclear fluctuations in atomistic modelling is possible by employing path integral techniques, which involve a considerable computational overhead due to the need of simulating multiple replicas of the…

Chemical Physics · Physics 2017-03-23 Venkat Kapil , Jörg Behler , Michele Ceriotti

A general asynchronous alternating iterative model is designed, for which convergence is theoretically ensured both under classical spectral radius bound and, then, for a classical class of matrix splittings for $\mathsf H$-matrices. The…

Numerical Analysis · Mathematics 2023-12-29 Guillaume Gbikpi-Benissan , Qinmeng Zou , Frédéric Magoulès

Hidden Markov Models (HMMs) can be accurately approximated using co-occurrence frequencies of pairs and triples of observations by using a fast spectral method in contrast to the usual slow methods like EM or Gibbs sampling. We provide a…

Machine Learning · Statistics 2012-03-29 Dean P. Foster , Jordan Rodu , Lyle H. Ungar

Zernike radial polynomials (ZRP) play a significant role in application areas such as optics design, imaging systems, and image processing systems. Currently, there are two kinds of numerical schemes for computing the ZRP automatically with…

Numerical Analysis · Mathematics 2024-08-20 Hong-Yan Zhang , Yu Zhou , Zhi-Qiang Feng

We develop a new method of umbral nature to treat blocks of Hermite and of Hermite like polynomials as independent algebraic quantities. The Calculus we propose allows the formulation of a number of practical rules allowing significant…

Classical Analysis and ODEs · Mathematics 2016-09-27 G. Dattoli , B. Germano , S. Licciardi , M. R. Martinelli
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