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This work shows that it is possible to calculate numerical values of the Chandrasekhar $H$-function for isotropic scattering at least with 15-digit accuracy by making use of the double exponential formula (DE-formula) of Takahashi and Mori…

Instrumentation and Methods for Astrophysics · Physics 2016-12-07 Kiyoshi Kawabata

This work shows that notable acceleration of the speed of calculating Chandrasekhar's H-functions for general laws of scattering with an iterative method can be realized by supplying a starting pproximation produced by the following…

Instrumentation and Methods for Astrophysics · Physics 2017-01-10 Kiyoshi Kawabata

This study provides an exact solution to Chandrasekhar's H function for isotropic scattering. The H function, which is governed by a nonlinear integral equation, plays a central role in radiative transfer theory. To facilitate the solution,…

Mathematical Physics · Physics 2026-04-03 Fikret Anli

In this paper, the new forms obtained for Chandrasekhar's H- function in Radiative Transfer by one of the authors both for non-conservative and conservative cases for isotropic scattering in a semi-infinite plane parallel atmosphere are…

Astrophysics · Physics 2007-11-22 Rabindra Nath Das , Rasajit Bera

We have established an iterative scheme to calculate with 15-digit accuracy the numerical values of Ambartsumian-Chandrasekhar's H-functions for anisotropic scattering characterized by the four-term phase function: the method incorporates…

Instrumentation and Methods for Astrophysics · Physics 2017-12-14 Kiyoshi Kawabata

Chandrasekhar's H(mu)-function forms the foundation of radiative transfer theory for semi-infinite, isotropically scattering atmospheres under external illumination. However, the classical formulation does not account for thermal emission…

Earth and Planetary Astrophysics · Physics 2026-04-28 Soumya Sengupta , Manika Singla , Fikret Anli

Numerical calculations of light propagation in random media demand the multiply scattered Stokes intensities to be written in a common fixed reference. A particularly useful way to perform automatically these basis transformations is to…

Optics · Physics 2010-10-19 Alexandre Souto Martinez , Tiago Jose Arruda

This article studies the problem of approximating functions belonging to a Hilbert space $H_d$ with an isotropic or anisotropic Gaussian reproducing kernel, $$ K_d(\bx,\bt) = \exp\left(-\sum_{\ell=1}^d\gamma_\ell^2(x_\ell-t_\ell)^2\right) \…

Numerical Analysis · Mathematics 2015-01-16 Gregory E. Fasshauer , Fred J. Hickernell , Henryk Woźniakowski

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

Numerical interpolation techniques are widely employed for calculating large rational functions in scattering amplitude computations. It has been observed in recent years that these rational functions greatly simplify upon partial…

High Energy Physics - Phenomenology · Physics 2024-12-31 Herschel A. Chawdhry

Context: The analytical results of Chandrasekhar's semi-infinite diffuse reflection problem is crucial in the context of stellar or planetary atmosphere. However, the atmospheric emission effect was not taken into account in this model, and…

Earth and Planetary Astrophysics · Physics 2021-05-05 Soumya Sengupta

For chaotic scattering on quantum graphs, the semiclassical approximation is exact. We use this fact and employ supersymmetry, the colour-flavour transformation, and the saddle-point approximation to calculate the exact expression for the…

Chaotic Dynamics · Physics 2015-06-16 Z. Pluhar , H. A. Weidenmüller

Study of scattering process in the nonlocal interaction framework leads to an integro-differential equation. The purpose of the present work is to develop an efficient approach to solve this integro-differential equation with high degree of…

Nuclear Theory · Physics 2018-08-09 N. J. Upadhyay , A. Bhagwat

We consider the approximation of the inverse square root of regularly accretive operators in Hilbert spaces. The approximation is of rational type and comes from the use of the Gauss-Legendre rule applied to a special integral formulation…

Numerical Analysis · Mathematics 2022-02-04 Eleonora Denich , Paolo Novati

In this work we provide a non-perturbative solution to the theoretical problem of extracting scattering amplitudes from Euclidean correlators in infinite volume. We work within the solid axiomatic framework of the Haag-Ruelle scattering…

High Energy Physics - Lattice · Physics 2024-07-03 Agostino Patella , Nazario Tantalo

In this paper we analyze a greedy procedure to approximate a linear functional defined in a Reproducing Kernel Hilbert Space by nodal values. This procedure computes a quadrature rule which can be applied to general functionals, including…

Numerical Analysis · Mathematics 2021-05-19 Gabriele Santin , Toni Karvonen , Bernard Haasdonk

We give a comprehensive presentation of methods for calculating the Casimir force to arbitrary accuracy, for any number of objects, arbitrary shapes, susceptibility functions, and separations. The technique is applicable to objects immersed…

Quantum Physics · Physics 2010-08-23 Sahand Jamal Rahi , Thorsten Emig , Noah Graham , Robert L. Jaffe , Mehran Kardar

The integro-differential formulation of the RTE and its solution by iterations on the source has been extended here to handle anisotropic scattering. The iterative part of the method is O(N ln N ), thanks to an efficient use of H-matrices.…

Numerical Analysis · Mathematics 2023-06-12 Olivier Pironneau , Pierre-Henri Tournier

We consider the use of rational basis functions to compute the scattering and inverse scattering transforms associated with the AKNS system. The proposed numerical forward scattering transform computes the solution of the AKNS system that…

Numerical Analysis · Mathematics 2021-07-02 Thomas Trogdon

The solutions of the \textit{diffuse reflection finite atmosphere problem} are very useful in the astrophysical context. Chandrasekhar was the first to solve this problem analytically, by considering atmospheric scattering. These results…

Earth and Planetary Astrophysics · Physics 2022-09-21 Soumya Sengupta
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