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A boundary integral formulation for the solution of the Helmholtz equation is developed in which all traditional singular behaviour in the boundary integrals is removed analytically. The numerical precision of this approach is illustrated…

Computational Physics · Physics 2019-10-02 Q. Sun , E. Klaseboer , B. C. Khoo , D. Y. C. Chan

Others have solved the Schr\"odinger equation for a one-dimensional model having a square potential barrier in free-space by requiring an incident and a reflected wave in the semi-infinite pre-barrier region, two opposing waves in the…

Quantum Physics · Physics 2023-05-03 Mark J. Hagmann

We present strongly stable semi-discrete finite difference approximations to the quarter space problem (x>0, t>0) for the first order in time, second order in space wave equation with a shift term. We consider space-like (pure outflow) and…

General Relativity and Quantum Cosmology · Physics 2024-07-11 Gioel Calabrese , Carsten Gundlach

We consider the problem of numerically approximating the solutions to an elliptic partial differential equation (PDE) for which the boundary conditions are lacking. To alleviate this missing information, we assume to be given measurement…

Numerical Analysis · Mathematics 2024-06-07 Andrea Bonito , Diane Guignard

We study the one-dimensional Helmholtz equation with (possibly perturbed) quasiperiodic coefficients. Quasiperiodic functions are the restriction of higher dimensional periodic functions along a certain (irrational) direction. In classical…

Analysis of PDEs · Mathematics 2026-02-10 Pierre Amenoagbadji , Sonia Fliss , Patrick Joly

A finite element approach for approximating the solution of a mathematical model for the response of a penetrable, bounded object (obstacle) to the excitation by an external electromagnetic field is presented and investigated. The model…

Numerical Analysis · Mathematics 2026-04-16 Lutz Angermann

Two boundary value problems for the Helmholtz equation in a semi-infinite strip are considered. The main feature of these problems is that, in addition to the function and its normal derivative on the boundary, the functionals of the…

Analysis of PDEs · Mathematics 2016-04-26 Y. A. Antipov

In the aim to find the simplest and most efficient shape of a noise absorbing wall to dissipate the acoustical energy of a sound wave, we consider a frequency model described by the Helmholtz equation with a damping on the boundary. The…

Analysis of PDEs · Mathematics 2020-07-23 Frédéric Magoulès , Thi Phuong Kieu Nguyen , Pascal Omnes , Anna Rozanova-Pierrat

This work introduces a novel Trefftz Continuous Galerkin (TCG) method for 2D Helmholtz problems based on evanescent plane waves (EPWs). We construct a new globally-conforming discrete space, departing from standard discontinuous Trefftz…

Numerical Analysis · Mathematics 2025-12-03 Nicola Galante , Bruno Després , Emile Parolin

In this paper, we propose a new and unified approach for nonparametric regression and conditional distribution learning. Our approach simultaneously estimates a regression function and a conditional generator using a generative learning…

Machine Learning · Statistics 2023-06-28 Shanshan Song , Tong Wang , Guohao Shen , Yuanyuan Lin , Jian Huang

Computer algebra can answer various questions about partial differential equations using symbolic algorithms. However, the inclusion of data into equations is rare in computer algebra. Therefore, recently, computer algebra models have been…

Machine Learning · Computer Science 2022-06-28 Markus Lange-Hegermann , Daniel Robertz

Solving the wave equation is one of the most (if not the most) fundamental problems we face as we try to illuminate the Earth using recorded seismic data. The Helmholtz equation provides wavefield solutions that are dimensionally reduced,…

Geophysics · Physics 2021-06-04 Tariq Alkhalifah , Chao Song , Umair bin Waheed , Qi Hao

For a spinless quantum particle in a one-dimensional box or an electromagnetic wave in a one-dimensional cavity, the respective Dirichlet and Neumann boundary conditions both lead to non-degenerate wave functions. However, in two spatial…

Negative refractive index materials have attracted significant research attention due to their unique electromagnetic response characteristics. In this paper, we employ the complementing boundary condition to establish rigorous a priori…

Analysis of PDEs · Mathematics 2025-05-28 Wenjing Zhang , Yu Chen , Yixian Gao

We investigate elliptic fractional equations in the whole space, involving zero order perturbations of the fractional Laplacian $(-\Delta)^s$, $0<s<1$. Our main objective is to determine appropriate radiation conditions at infinity that…

Analysis of PDEs · Mathematics 2026-02-23 Dana Zilberberg , Fioralba Cakoni , Michael S. Vogelius

In the computation of compressible fluid flows, numerical boundary conditions are always necessary for all physical variables at computational boundaries while just partial physical variables are often prescribed as physical boundary…

Numerical Analysis · Mathematics 2022-04-13 Jiequan Li , Qinglong Zhang

A simple transformation converts a solution of a partial differential equation with a Dirichlet boundary condition to a function satisfying a Robin (generalized Neumann) condition. In the simplest cases this observation enables the exact…

Mathematical Physics · Physics 2009-11-10 J. D. Bondurant , S. A. Fulling

Artificial boundary conditions (BCs) play a ubiquitous role in numerical simulations of transport phenomena in several diverse fields, such as fluid dynamics, electromagnetism, acoustics, geophysics, and many more. They are essential for…

Fluid Dynamics · Physics 2025-04-30 Friedemann Klass , Alessandro Gabbana , Andreas Bartel

In this paper, we consider a class of nonlinear fractional differential equations involving Hilfer derivative with boundary conditions. First, we obtain an equivalent integral for the given boundary value problem in weighted space of…

General Mathematics · Mathematics 2019-10-01 Mohammed S Abdo , S K Panchal , Sandeep P Bhairat

Various methods of treating outer boundaries in numerical relativity are compared using a simple test problem: a Schwarzschild black hole with an outgoing gravitational wave perturbation. Numerical solutions computed using different…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Oliver Rinne , Lee Lindblom , Mark A. Scheel