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The pole condition approach for deriving transparent boundary conditions is extended to the time-dependent, two-dimensional case. Non-physical modes of the solution are identified by the position of poles of the solution's spatial Laplace…

Numerical Analysis · Mathematics 2015-07-28 Daniel Ruprecht , Achim Schädle , Frank Schmidt

Magnetic singularities known as Bloch points (BPs) present a fundamental challenge for micromagnetic theory, which is based on the assumption of a fixed magnetization vector length. Due to the divergence of the effective field at a BP,…

Mesoscale and Nanoscale Physics · Physics 2026-03-18 Vladyslav M. Kuchkin , Andreas Haller , Andreas Michels , Thomas L. Schmidt , Nikolai S. Kiselev

Simulations of magnetization dynamics in a multiscale environment enable rapid evaluation of the Landau-Lifshitz-Gilbert equation in a mesoscopic sample with nanoscopic accuracy in areas where such accuracy is required. We have developed a…

Computational Physics · Physics 2016-11-28 Andrea De Lucia , Benjamin Krüger , Oleg A. Tretiakov , Mathias Kläui

We formulate and demonstrate experimentally the high-resolution spectral method based on Bloch-wave symmetry properties for extracting mode dispersion in periodic waveguides from measurements of near-field profiles. We characterize both the…

A new numerical method is developed to approximate the solution of Laplace's equation in the exterior of the sphere with a strongly nonlinear boundary value of oblique type. A functional analysis attempt to solve this type of boundary…

Numerical Analysis · Mathematics 2025-06-30 Mriganka Shekhar Chaki , Maria C. Jorge

The Landau-Lifshitz equation governing magnetization dynamics is written in terms of the amplitudes of normal modes associated with the micromagnetic system's appropriate ground state. This results in a system of nonlinear ordinary…

Other Condensed Matter · Physics 2022-01-19 S. Perna , F. Bruckner , C. Serpico , D. Suess , M. d'Aquino

This paper is concerned with a space-time adaptive numerical method for instationary porous media flows with nonlinear interaction between porosity and pressure, with focus on problems with discontinuous initial porosities. A convergent…

Numerical Analysis · Mathematics 2025-08-27 Markus Bachmayr , Simon Boisserée

The scattering of waves by obstacles in a 2D setting is considered, in particular the computation of the scattered field via the collocation or the least-squares methods. In the case of multiple scattering by smooth obstacles, we prove that…

Numerical Analysis · Mathematics 2014-01-15 Gilles Chardon

We study the systematic numerical approximation of Maxwell's equations in dispersive media. Two discretization strategies are considered, one based on a traditional leapfrog time integration method and the other based on convolution…

Numerical Analysis · Mathematics 2020-04-02 Jürgen Dölz , Herbert Egger , Vsevolod Shashkov

We present numerical upscaling techniques for a class of linear second-order self-adjoint elliptic partial differential operators (or their high-resolution finite element discretization). As prototypes for the application of our theory we…

Numerical Analysis · Mathematics 2014-09-11 Axel Malqvist , Daniel Peterseim

We develop a volume penalization method for inhomogeneous Neumann boundary conditions, generalizing the flux-based volume penalization method for homogeneous Neumann boundary condition proposed by Kadoch et al. [J. Comput. Phys. 231 (2012)…

Numerical Analysis · Mathematics 2019-05-13 Teluo Sakurai , Katsunori Yoshimatsu , Naoya Okamoto , Kai Schneider

In this paper, we introduce a new approach to solving the porous medium equation using a moving mesh finite element method that leverages the Onsager variational principle as an approximation tool. Both the continuous and discrete problems…

Numerical Analysis · Mathematics 2024-04-01 Si Xiao , Xianmin Xu

We suggest a method of construction of general diffeomorphism invariant boundary conditions for metric fluctuations. The case of $d+1$ dimensional Euclidean disk is studied in detail. The eigenvalue problem for the Laplace operator on…

General Relativity and Quantum Cosmology · Physics 2009-10-28 Valeri Marachevsky , Dmitri Vassilevich

A new method is presented for solving the momentum-space Schrodinger equation with a linear potential. The Lande-subtracted momentum space integral equation can be transformed into a matrix equation by the Nystrom method. The method…

High Energy Physics - Phenomenology · Physics 2009-11-07 Alfred Tang , John W. Norbury

In this article, we study eigenvalue problems associated to self-adjoint operators and their approximation obtained by subspace projection, as used in the reduced basis method for instance. We provide error bounds between the exact…

Mathematical Physics · Physics 2025-06-16 Louis Garrigue , Benjamin Stamm

In this article, we propose a reduced basis method for parametrized non-symmetric eigenvalue problems arising in the loading pattern optimization of a nuclear core in neutronics. To this end, we derive a posteriori error estimates for the…

Numerical Analysis · Mathematics 2023-07-13 Yonah Conjungo Taumhas , Geneviève Dusson , Virginie Ehrlacher , Tony Lelièvre , François Madiot

In this work we investigate the emergence of the localization regime for diffusion in various geometries: inside slabs, inside cylinders and around rods arranged on a square array. At high gradients, the transverse magnetization is strongly…

Medical Physics · Physics 2019-11-05 Nicolas Moutal , Kerstin Demberg , Denis Grebenkov , Tristan Anselm Kuder

Well-known Bloch equations describe the spin systems (electronic and nuclear) for any scale of time, from transient processes to steady states. Usually in solids T_2 << T_1. The question arises: what are the approximations that should be…

Other Condensed Matter · Physics 2010-06-08 M. D. Zviadadze , N. D. Chachava , A. G. Kvirikadze , A. K. Pokleba

We consider nodal-based Lagrangian interpolations for the finite element approximation of the Maxwell eigenvalue problem. The first approach introduced is a standard Galerkin method on Powell-Sabin meshes, which has recently been shown to…

Numerical Analysis · Mathematics 2023-04-04 Daniele Boffi , Ramon Codina , Önder Türk

The authors propose a Nystrom method to approximate the solution of a boundary integral equation connected with the exterior Neumann problem for Laplace's equation on planar domains with corners. They prove the convergence and the stability…

Numerical Analysis · Mathematics 2015-04-15 Luisa Fermo , Concetta Laurita