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This article investigates the full Boltzmann equation up to second order in the cosmological perturbations. Describing the distribution of polarized radiation by using a tensor valued distribution function, the second order Boltzmann…

Astrophysics · Physics 2009-12-03 Cyril Pitrou

We introduce a non-exponential radiative framework that takes into account the local spatial correlation of scattering particles in a medium. Most previous works in graphics have ignored this, assuming uncorrelated media with a uniform,…

Graphics · Computer Science 2018-05-14 Adrian Jarabo , Carlos Aliaga , Diego Gutierrez

Radiative transfer in curved spacetimes has become increasingly important to understanding high-energy astrophysical phenomena and testing general relativity in the strong field limit. The equations of radiative transfer are physically…

Astrophysics · Physics 2009-11-13 Avery E. Broderick

Scalar-tensor gravity theories with a nonminimal Gauss-Bonnet coupling typically lead to an anomalous propagation speed for gravitational waves, and have therefore been tightly constrained by multimessenger observations such as…

General Relativity and Quantum Cosmology · Physics 2019-12-18 José Barrientos , Fabrizio Cordonier-Tello , Cristóbal Corral , Fernando Izaurieta , Perla Medina , Eduardo Rodríguez , Omar Valdivia

Using a so-called hemispherical model we derive a general transport equation for cosmic ray and thermal particles scattered in pitch angle by magnetic inhomogeneities in a moving collisionless plasma. The weak scattering through 90 degrees…

Astrophysics · Physics 2009-11-11 V. N. Zirakashvili

A theory of electromagnetic wave propagation in a weakly anisotropic smoothly inhomogeneous medium is developed, based on the quantum-mechanical diagonalization procedure applied to Maxwell equations. The equations of motion for the…

Optics · Physics 2008-11-26 K. Yu. Bliokh , D. Yu. Frolov , Yu. A. Kravtsov

In a recent work [20], we predicted and experimentally validated a new physical mechanism for altering the propagation path of a monochromatic beam. Specifically, we showed that by properly tailoring the spatial distribution of the linear…

Optics · Physics 2023-05-24 J. M. Nichols , D. V. Nickel , G. K. Rohde , F. Bucholtz

We study the paraxial wave equation with a randomly perturbed index of refraction, which can model the propagation of a wave beam in a turbulent medium. The random perturbation is a stationary and isotropic process with a general form of…

Analysis of PDEs · Mathematics 2022-05-10 Liliana Borcea , Josselin Garnier , Knut Solna

The cosmological propagation of tensor perturbations is studied in the context of parity-violating extensions of the symmetric teleparallel equivalent of General Relativity theory. This non-Riemannian formulation allows for a wider variety…

General Relativity and Quantum Cosmology · Physics 2019-12-11 Aindriú Conroy , Tomi Koivisto

Light transport in graded index media follows a curved trajectory determined by the Fermat's principle. Besides the effect of variation of the refractive index on the transport of radiative intensity, the curved ray trajectory will induce…

Classical Physics · Physics 2015-05-30 J. M. Zhao , J. Y. Tan , L. H. Liu

For geometric systems of real principal type, we define a subprincipal symbol and derive a transport equation for polarizations which, in the scalar case, is a well-known equation of Duistermaat and H\"ormander. We apply the transport…

Analysis of PDEs · Mathematics 2022-06-28 Sönke Hansen

We present a general radiative transfer model which allows the Zeeman diagnostics of complex and unresolved solar magnetic fields. Present modeling techniques still rely to a large extent on a-priori assumptions about the geometry of the…

Astrophysics · Physics 2009-11-13 T. A. Carroll , M. Kopf

Numerical evidence of non-diffusive transport in three-dimensional, resistive pressure-gradient-driven plasma turbulence is presented. It is shown that the probability density function (pdf) of test particles' radial displacements is…

Plasma Physics · Physics 2009-11-10 D. del-Castillo-Negrete , B. A. Carreras , V. E. Lynch

The transport of non-thermal particles across a large-scale magnetic field in the presence of magnetised turbulence has been a long-standing issue in high-energy astrophysics. Of particular interest is the dependence of the parallel and…

High Energy Astrophysical Phenomena · Physics 2025-10-03 Marco Kuhlen , Vo Hong Minh Phan , Philipp Mertsch

Previous proposals to permit non-exponential free-path statistics in radiative transfer have not included support for volume and boundary sources that are spatially uncorrelated from the scattering events in the medium. Birth-collision free…

Computational Physics · Physics 2021-02-19 Eugene d'Eon

We analyze propagation equations for the polar modes of gravitational waves in cosmological space-times. We prove that polar gravitational waves must perturb the density and non-azimuthal components of the velocity of material medium of the…

General Relativity and Quantum Cosmology · Physics 2017-06-26 Wojciech Kulczycki , Edward Malec

This paper concerns the derivation of radiative transfer equations for acoustic waves propagating in a randomly fluctuating half-space in the weak-scattering regime, and the study of boundary effects through an asymptotic analysis of the…

Classical Physics · Physics 2022-12-01 Adel Messaoudi , Regis Cottereau , Christophe Gomez

We present the geometry and symmetries of radiative transfer theory. Our geometrization exploits recent work in the literature that enables to obtain the Hamiltonian formulation of radiative transfer as the semiclassical limit of a phase…

Mathematical Physics · Physics 2013-07-30 Christian Lessig , Alex L. Castro

Starting from first principles, we formulate a theory of wave packet propagation in a nonlinear, disordered medium of any dimension, through the derivation of a Fokker-Planck transport equation. Our theory is based on a diagrammatic…

Disordered Systems and Neural Networks · Physics 2011-10-28 Nicolas Cherroret , Thomas Wellens

A non-minimal photon-torsion axial coupling in the quantum electrodynamics (QED) framework is considered. The geometrical optics in Riemannian-Cartan spacetime is considering and a plane wave expansion of the electromagnetic vector…

General Relativity and Quantum Cosmology · Physics 2007-05-23 L. C. Garcia de Andrade
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