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The present work provides a comprehensive study of symmetric-conjugate operator splitting methods in the context of linear parabolic problems and demonstrates their additional benefits compared to symmetric splitting methods. Relevant…

Numerical Analysis · Mathematics 2024-01-10 Sergio Blanes , Fernando Casas , Cesáreo González , Mechthild Thalhammer

We present a high-order accurate boundary-based solver for three-dimensional (3D) frequency-domain scattering from a doubly-periodic grating of smooth axisymmetric sound-hard or transmission obstacles. We build the one-obstacle solution…

Numerical Analysis · Mathematics 2016-09-21 Yuxiang Liu , Alex H. Barnett

We obtain a nonperturbative, analytical solution to integral equation of scattering theory by assuming the field within the scattering object is a spherical wave with a scattering amplitude equal to that of the far field. This approximation…

Classical Physics · Physics 2018-09-26 Brian Slovick , Srini Krishnamurthy

The efficient numerical solution of Non-LTE multilevel transfer problems requires the combination of highly convergent iterative schemes with fast and accurate formal solution methods of the radiative transfer (RT) equation. This…

Astrophysics · Physics 2007-10-30 P. Fabiani Bendicho , J. Trujillo Bueno

Higher-order accurate solution to electromagnetic scattering problems are obtained at reduced computational cost in a {\it p}-variable finite volume time domain method. Spatial operators of lower, including first-order accuracy, are…

Computational Physics · Physics 2017-09-07 A. Chatterjee , S. M. Joshi

We construct a scattering theory for harmonic one-forms on Riemann surfaces, obtained from boundary value problems through systems of curves and the jump problem. We obtain an explicit expression for the scattering matrix in terms of…

Differential Geometry · Mathematics 2021-12-03 Eric Schippers , Wolfgang Staubach

In this paper, we consider the following three dimensional defocusing cubic nonlinear Schr\"odinger equation (NLS) with partial harmonic potential \begin{equation*}\tag{NLS} i\partial_t u + \left(\Delta_{\mathbb{R}^3 }-x^2 \right) u = |u|^2…

Analysis of PDEs · Mathematics 2024-11-27 Xing Cheng , Chang-Yu Guo , Zihua Guo , Xian Liao , Jia Shen

Line scattering polarization can be strongly affected by Rayleigh scattering by neutral hydrogen and Thompson scattering by free electrons. Often a continuum depolarization results, but the Doppler redistribution produced by the continuum…

Solar and Stellar Astrophysics · Physics 2015-06-18 T. del Pino Alemán , R. Manso Sainz , J. Trujillo Bueno

We present a new method for computing the Near-To-Far-Field (NTFF) transformation in FDTD simulations which has an overall scaling of $O(N^3)$ instead of the standard $O(N^4)$. By mapping the far field with a cartesian coordinate system the…

Computational Physics · Physics 2013-11-05 Travis Garrett

We present the first numerical radiative transfer simulation of multiple light scattering in dust configurations containing aligned non-spherical (spheroidal) dust grains. Such models are especially important if one wants to explain the…

Astrophysics · Physics 2009-11-07 S. Wolf , N. V. Voshchinnikov , Th. Henning

We present a general-purpose solver for convex quadratic programs based on the alternating direction method of multipliers, employing a novel operator splitting technique that requires the solution of a quasi-definite linear system with the…

Optimization and Control · Mathematics 2020-02-13 Bartolomeo Stellato , Goran Banjac , Paul Goulart , Alberto Bemporad , Stephen Boyd

In this paper we demonstrate a computational method to solve the inverse scattering problem for a star-shaped, smooth, penetrable obstacle in 2D. Our method is based on classical ideas from computational geometry. First, we approximate the…

Monte Carlo radiative transfer (MCRT) simulations are a powerful tool for determining the appearance of astrophysical objects, analyzing the prevalent physical conditions within them, and inferring their properties on the basis of real…

Instrumentation and Methods for Astrophysics · Physics 2023-12-13 Anton Krieger , Sebastian Wolf

The interpretation of the intensity and polarization of the spectral line radiation produced in the atmosphere of the Sun and of other stars requires solving a radiative transfer problem that can be very complex, especially when the main…

Solar and Stellar Astrophysics · Physics 2015-06-16 Jiri Stepan , Javier Trujillo Bueno

We present a systematic formulation of scattering theory for nonlinear interactions in one dimension and develop a nonlinear generalization of the transfer matrix that has a composition property similar to its linear analog's. We offer…

Quantum Physics · Physics 2019-01-25 Ali Mostafazadeh

We analyze one particle, two-center quantum problems which admit separation of variables in prolate spheroidal coordinates, a natural restriction satisfied by the H$_2^+$ molecular ion. The symmetry operator is constructed explicitly. We…

Mathematical Physics · Physics 2016-06-30 Willard Miller, , Alexander V Turbiner

This article presents an on-line tool (rttools.irap.omp.eu) and its accompanying software ressources for the numerical solution of basic radiation transfer out of local thermodynamic equilibrium (LTE). State-of-the-art stationary iterative…

Instrumentation and Methods for Astrophysics · Physics 2015-12-09 J. Lambert , F. Paletou , E. Josselin , J. -M. Glorian

This paper is concerned with a 1D Schr\"odinger scattering problem involving both oscillatory and evanescent regimes, separated by jump discontinuities in the potential function, to avoid "turning points". We derive a non-overlapping domain…

Numerical Analysis · Mathematics 2016-06-17 Anton Arnold , Claudia Negulescu

We study non-local exchange and scattering operators arising in domain decomposition algorithms for solving elliptic problems on domains in $\mathbb{R}^2$. Motivated by recent formulations of the Optimized Schwarz Method introduced by…

Numerical Analysis · Mathematics 2025-04-09 Thomas Beck , Yaiza Canzani , Jeremy L. Marzuola

The split-operator technique for wave packet propagation in quantum systems is expanded here to the case of propagating wave functions describing Schr\"odinger particles, namely, charge carriers in semiconductor nanostructures within the…

Mesoscale and Nanoscale Physics · Physics 2016-01-05 Andrey Chaves , G. A. Farias , F. M. Peeters , R. Ferreira