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Related papers: Quasiperiodic Elliptic Operators: Projection Metho…

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A fast explicit operator splitting (FEOS) method for the molecular beam epitaxy model has been presented in [Cheng, et al., Fast and stable explicit operator splitting methods for phase-field models, J. Comput. Phys., submitted]. The…

Numerical Analysis · Mathematics 2015-11-30 Xiao Li , Zhonghua Qiao , Hui Zhang

A specialized algorithm for quadratic optimization (QO, or, formerly, QP) with disjoint linear constraints is presented. In the considered class of problems, a subset of variables are subject to linear equality constraints, while variables…

Optimization and Control · Mathematics 2019-09-12 Tijana Janjic , Yvonne Ruckstuhl , Philippe L. Toint

Quasiperiodic systems, related to irrational numbers, are space-filling structures without decay nor translation invariance. How to accurately recover these systems, especially for non-smooth cases, presents a big challenge in numerical…

Numerical Analysis · Mathematics 2024-01-08 Kai Jiang , Qi Zhou , Pingwen Zhang

We study spectral properties of second order elliptic operators with periodic coefficients in dimension two. These operators act in periodic simply-connected waveguides, with either Dirichlet, or Neumann, or the third boundary condition.…

Spectral Theory · Mathematics 2007-05-23 E. Shargorodsky , A. V. Sobolev

In this paper, we design and analyze a Hybrid-High Order (HHO) approximation for a class of quasilinear elliptic problems of nonmonotone type. The proposed method has several advantages, for instance, it supports arbitrary order of…

Numerical Analysis · Mathematics 2021-11-01 Thirupathi Gudi , Gouranga Mallik , Tamal Pramanick

In these lectures we develop the projection operator method for quantum groups. Here the term "quantum groups" means q-deformed universal enveloping algebras of contragredient Lie (super)algebras of finite growth. Contains of the lectures…

Quantum Algebra · Mathematics 2007-05-23 V. N. Tolstoy

In this paper, we propose and analyze a multiscale method for a class of quasilinear elliptic problems of nonmonotone type with spatially multiscale coefficient. The numerical approach is inspired by the Localized Orthogonal Decomposition…

Numerical Analysis · Mathematics 2025-07-28 Maher Khrais , Barbara Verfürth

We consider an iteration method for solving an elliptic type boundary value problem $\mathcal{A} u=f$, where a positive definite operator $\mathcal{A}$ is generated by a quasi--periodic structure with rapidly changing coefficients (typical…

Numerical Analysis · Mathematics 2017-01-03 B. Khoromskij , S. Repin

We continue our earlier studies of quasi-periodic oscillations (QPOs) in the power spectra of accreting, rapidly-rotating black holes that originate from the geometric "light echoes" of X-ray flares occurring within the black hole…

High Energy Astrophysical Phenomena · Physics 2009-11-13 Keigo Fukumura , Demosthenes Kazanas , Gordon Stephenson

This work is concerned with two-spin-1/2-fermion relativistic quantum mechanics, and it is about the construction of one-particle projectors using an inherently two(many)-particle, `explicitly correlated' basis representation, necessary for…

Chemical Physics · Physics 2024-06-12 Péter Hollósy , Péter Jeszenszki , Edit Mátyus

Astronomy is presently experiencing profound growth in the deployment of machine learning to explore large datasets. However, transient quasi-periodic oscillations (QPOs) which appear in power density spectra of many X-ray binary system…

High Energy Astrophysical Phenomena · Physics 2023-06-28 Thaddaeus J. Kiker , James F. Steiner , Cecilia Garraffo , Mariano Mendez , Liang Zhang

We construct and analyze approximation rates of deep operator networks (ONets) between infinite-dimensional spaces that emulate with an exponential rate of convergence the coefficient-to-solution map of elliptic second-order partial…

Numerical Analysis · Mathematics 2023-11-27 Carlo Marcati , Christoph Schwab

We establish a new decomposition formula for two orthogonal projections P and Q on a separable Hilbert space V. This formula yields an orthogonal direct sum decomposition of V into invariant subspaces under P and Q, each of which is either…

Representation Theory · Mathematics 2026-04-24 Yuki Fujii , Toyohiro Tsurumaru

Eigenvalue problems for elliptic operators play an important role in science and engineering applications, where efficient and accurate numerical computation is essential. In this work, we propose a novel operator inference approach for…

Numerical Analysis · Mathematics 2025-04-23 Haoqian Li , Jiguang Sun , Zhiwen Zhang

We prove global subelliptic estimates for quadratic differential operators. Quadratic differential operators are operators defined in the Weyl quantization by complex-valued quadratic symbols. In a previous joint work with M. Hitrik, we…

Analysis of PDEs · Mathematics 2008-09-02 Karel Pravda-Starov

We study the contraction semigroups of elliptic quadratic differential operators. Elliptic quadratic differential operators are the non-selfadjoint operators defined in the Weyl quantization by complex-valued elliptic quadratic symbols. We…

Analysis of PDEs · Mathematics 2007-05-23 Karel Pravda-Starov

Computing many eigenpairs of the Schr{\"o}dinger operator presents a computational bottleneck in large-scale quantum simulations due to the global communication overhead of explicit orthogonalization. To address this issue, we propose a…

Numerical Analysis · Mathematics 2026-05-26 Shengyue Wang , Aihui Zhou

Quantum light pulses (QLPs) can be described by spatio-temporal modes, each of which is associated with a quantum state. In the mid-infrared spectral range, electro-optic sampling (EOS) provides a means to characterize quantum fluctuations…

Quantum Physics · Physics 2026-01-07 Geehyun Yang , Sandeep Sharma , Andrey S. Moskalenko

The accuracy of the electric field integral equation (EFIE) can be substantially improved using high-order discretizations. However, this equation suffers from ill-conditioning and deleterious numerical effects in the low-frequency regime,…

Numerical Analysis · Mathematics 2023-08-30 Johann Bourhis , Adrien Merlini , Francesco P. Andriulli

We report an all-electron implementation of the quasiparticle self-consistent GW (QSGW) method for molecular and periodic systems within the framework of numerical atomic orbitals (NAOs), as implemented in the LibRPA software package. Our…

Materials Science · Physics 2026-05-22 Bohan Jia , Min-Ye Zhang , Ziqing Guan , Huanjing Gong , Xinguo Ren