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Vertex-frequency analysis, particularly the windowed graph Fourier transform (WGFT), is a significant challenge in graph signal processing. Tight frame theories is known for its low computational complexity in signal reconstruction, while…

Signal Processing · Electrical Eng. & Systems 2024-12-31 Linbo Shang , Zhichao Zhang

We investigate the complex-time analytic structure of solutions of the 3D-axisymmetric, wall-bounded, incompressible Euler equations, by starting with the initial data proposed in Luo and Hou (2014), to study a possible finite-time…

Fluid Dynamics · Physics 2024-06-07 Sai Swetha Venkata Kolluru , Rahul Pandit

We develop an effective computational tool for simulating the scattering of 1D waves by a composite layer architected in an otherwise homogeneous medium. The layer is designed as the union of segments cut from various mother periodic media,…

Computational Physics · Physics 2025-11-19 Prasanna Salasiya , Bojan B. Guzina

We propose a novel method to reconstruct the spatio-temporal amplitude and phase of the electric field of ultrashort laser pulses using spatially-resolved spectral interferometry. This method is based on a fiber-optic coupler interferometer…

Solving time-harmonic wave propagation problems by iterative methods is a difficult task, and over the last two decades, an important research effort has gone into developing preconditioners for the simplest representative of such wave…

Numerical Analysis · Mathematics 2018-02-22 Martin J. Gander , Hui Zhang

In this article, we determine the wave front sets of solutions to time dependent Schr\"odinger equations with a sub-quadratic potential by using the representation of the Schr\"dingier evolution operator via wave packet transform (short…

Analysis of PDEs · Mathematics 2014-08-11 Keiichi Kato , Shingo Ito

A Python package for the calculation of spectrograms with optimized time and frequency resolution for application in the analysis of numerical simulations on ultrashort pulse propagation is presented. Gabor's uncertainty principle prevents…

Computational Physics · Physics 2018-09-05 O. Melchert , B. Roth , U. Morgner , A. Demircan

This report aims to present my research updates on distance function wavelets (DFW) based on the fundamental solutions and the general solutions of the Helmholtz, modified Helmholtz, and convection-diffusion equations, which include the…

Computational Engineering, Finance, and Science · Computer Science 2025-10-20 W. Chen

This paper presents a new methodology for the solution of problems of two- and three-dimensional acoustic scattering (and, in particular, two-dimensional electromagnetic scattering) by obstacles and defects in presence an arbitrary number…

Numerical Analysis · Mathematics 2017-08-23 Oscar P. Bruno , Carlos Pérez-Arancibia

For problems of time-harmonic scattering by rational polygonal obstacles, embedding formulae express the far-field pattern induced by any incident plane wave in terms of the far-field patterns for a relatively small (frequency-independent)…

Numerical Analysis · Mathematics 2024-03-06 A. Gibbs , S. Langdon

This paper is a contribution to the old problem of representing a signal in the coordinates of time and frequency. As the starting point, we abandon Gabor's complex extension and re-evaluate fundamental principles of time-frequency…

Complex Variables · Mathematics 2015-09-28 Steven Sandoval , Phillip L. De Leon

We propose an iterative solution method for the 3D high-frequency Helmholtz equation that exploits a contour integral formulation of spectral projectors. In this framework, the solution in certain invariant subspaces is approximated by…

Numerical Analysis · Mathematics 2018-11-30 Xiao Liu , Yuanzhe Xi , Yousef Saad , Maarten V. de Hoop

Transverse magnetic (TM) scattering of an electromagnetic wave from a periodic dielectric diffraction grating can mathematically be described by a volume integral equation. This volume integral equation, however, in general fails to feature…

Numerical Analysis · Mathematics 2012-11-19 Armin Lechleiter , Dinh Liem Nguyen

Trotterization-based, iterative approaches to quantum simulation are restricted to simulation times less than the coherence time of the quantum computer, which limits their utility in the near term. Here, we present a hybrid…

We propose a Bernoulli phase-fitted (BPF) finite difference method for the Helmholtz equation on the interval $(0, L)$ with impedance boundary conditions. The scheme is derived from a complexified Scharfetter--Gummel discretization of the…

Numerical Analysis · Mathematics 2026-05-21 Ansgar Jüngel , Panchi Li , Zhiwei Sun , Zhiwen Zhang

Within the expansive domain of optical sciences, achieving the precise characterization of light beams stands as a fundamental pursuit, pivotal for various applications, including telecommunications and imaging technologies. This study…

We propose a novel and simplified multiscale time integrator Fourier pseudospectral (MTI-FP) method for the Klein-Gordon-Schr\"odinger (KGS) equations with a dimensionless parameter epsilon in (0,1], where epsilon is inversely proportional…

Numerical Analysis · Mathematics 2026-05-14 Yue Feng , Caoyi Liu

We report a three-dimensional numerical implementation of multiconfiguration time-dependent Hartree-Fock (MCTDHF) based on a multi-resolution Cartesian grid, with no need to assume any symmetry of molecular structure. We successfully…

Computational Physics · Physics 2016-03-23 Ryohto Sawada , Takeshi Sato , Kenichi L. Ishikawa

It is well known that the Fourier series Dirichlet-to-Neumann (DtN) boundary condition can be used to solve the Helmholtz equation in unbounded domains. In this work, applying such DtN boundary condition and using the finite element method,…

Numerical Analysis · Mathematics 2019-02-12 Liwei Xu , Tao Yin

This paper is concerned with the time-dependent Maxwell's equations for a plane interface between a negative material described by the Drude model and the vacuum, which fill, respectively, two complementary half-spaces. In a first paper, we…

Analysis of PDEs · Mathematics 2021-10-14 Maxence Cassier , Christophe Hazard , Patrick Joly