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Simple finite differencing of the anisotropic diffusion equation, where diffusion is only along a given direction, does not ensure that the numerically calculated heat fluxes are in the correct direction. This can lead to negative…

Instrumentation and Methods for Astrophysics · Physics 2015-05-19 Prateek Sharma , Gregory W. Hammett

We consider the scattering of elastic waves by highly oscillating anisotropic periodic media with bounded support. Applying the two-scale homogenization, we first obtain a constant coefficient second-order partial differential elliptic…

Analysis of PDEs · Mathematics 2018-02-06 Yi-Hsuan Lin , Shixu Meng

We analyze the well-posedness of an anisotropic, nonlocal diffusion equation. Establishing an equivalence between weighted and unweighted anisotropic nonlocal diffusion operators in the vein of unified nonlocal vector calculus, we apply our…

Analysis of PDEs · Mathematics 2021-01-13 Marta D'Elia , Mamikon Gulian

The unbiased thermal diffusion of an overdamped Brownian particle in a square lattice potential is considered in the presence of an externally applied ac driving. The resulting diffusion matrix exhibits two orthogonal eigenvectors with…

Statistical Mechanics · Physics 2012-03-22 David Speer , Ralf Eichhorn , Peter Reimann

In this paper, we study optimization of the first eigenvalue of the heat equation with spatially nonuniform conductivity on a bounded domain under several constraints for the conductivity. We consider this problem in various boundary…

Optimization and Control · Mathematics 2015-04-23 Kaname Matsue , Hisashi Naito

In this paper, a new weighted first-order formulation is proposed for solving the anisotropic diffusion equations with deep neural networks. For many numerical schemes, the accurate approximation of anisotropic heat flux is crucial for the…

Numerical Analysis · Mathematics 2022-05-16 Hui Xie , Chuanlei Zhai , Li Liu , Heng Yong

In this paper we study the distribution of the temperature within a body where the heat is transported only by radiation. Specifically, we consider the situation where both emission-absorption and scattering processes take place. We study…

Analysis of PDEs · Mathematics 2025-10-01 Elena Demattè , Juan J. L. Velázquez

Nonlinear self-adjointness of the anisotropic nonlinear heat equation is investigated. Mathematical models of heat conduction in anisotropic media with a source are considered and a class of self-adjoint models is identified. Conservation…

Mathematical Physics · Physics 2012-02-28 Nail H. Ibragimov , Elena D. Avdonina

We describe the mathematical theory of diffusion and heat transport with a view to including some of the main directions of recent research. The linear heat equation is the basic mathematical model that has been thoroughly studied in the…

Analysis of PDEs · Mathematics 2017-06-27 Juan Luis Vázquez

An anisotropic random barrier model is presented, in which the transition probabilities in different directions have different probability density functions. At low temperatures, the anisotropic long--time diffusion coefficients, obtained…

Disordered Systems and Neural Networks · Physics 2009-11-10 Sebastian Bustingorry

We investigate diffusion equations which have concentration dependent diffusion coefficients with physically two relevant Ans\"atze, the self-similar and the traveling wave Ansatz. We found that for power-law concentration dependence some…

Statistical Mechanics · Physics 2023-11-09 I. F. Barna , L. Matyas

The anisotropic diffusion equation is imperative in understanding cosmic ray diffusion across the Galaxy, the heliosphere, and its interplay with the ambient magnetic field. This diffusion term contributes to the highly stiff nature of the…

High Energy Astrophysical Phenomena · Physics 2022-12-14 Pranab J. Deka , Lukas Einkemmer , Ralf Kissmann

We prove existence, uniqueness and regularity of solutions of nonlocal heat equations associated to anisotropic stable diffusion operators. The main features are that the right-hand side has very few regularity and that the spectral measure…

Analysis of PDEs · Mathematics 2018-12-20 Arturo de Pablo , Fernando Quirós , Ana Rodríguez

In this paper, we study the Helmholtz transmission eigenvalue problem for inhomogeneous anisotropic media with the index of refraction $n(x)\equiv 1$ in two and three dimension. Starting with a nonlinear fourth order formulation established…

Numerical Analysis · Mathematics 2023-04-26 Qing Liu , Tiexiang Li , Shuo Zhang

The concern of the present work is the introduction of a very efficient Asymptotic Preserving scheme for the resolution of highly anisotropic diffusion equations. The characteristic features of this scheme are the uniform convergence with…

Numerical Analysis · Mathematics 2014-04-08 Pierre Degond , Alexei Lozinski , Jacek Narski , Claudia Negulescu

In this paper we survey some recent results concerning scattering and non-scattering in the context of the linear Helmholtz equation and inhomogeneities of nontrivial contrast. We examine isotropic as well as anisotropic media. Part of the…

Analysis of PDEs · Mathematics 2026-02-09 Fioralba Cakoni , Michael S. Vogelius

The transmission eigenvalue problem arises from the inverse scattering theory for inhomogeneous media and has important applications in many qualitative methods. The problem is posted as a system of two second order partial differential…

Numerical Analysis · Mathematics 2020-01-16 Bo Gong , Jiguang Sun , Tiara Turner , Chunxiong Zheng

This paper addresses the topological structure of steady, anisotropic, inhomogeneous diffusion problems. Two discrete formulations: a) mixed and b) direct formulations are discussed. Differential operators are represented by sparse…

Numerical Analysis · Mathematics 2018-02-14 Marc Gerritsma , Artur Palha , Varun Jain , Yi Zhang

We consider the transport of conserved charges in spatially inhomogeneous quantum systems with a discrete lattice symmetry. We analyse the retarded two point functions involving the charge and the associated currents at long wavelengths,…

High Energy Physics - Theory · Physics 2017-12-20 Aristomenis Donos , Jerome P. Gauntlett , Vaios Ziogas

Anisotropic light transport is extremely common among scattering materials, yet a comprehensive picture of how macroscopic diffusion is determined by microscopic tensor scattering coefficients is not fully established yet. In this work, we…

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