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The idea of replacing an edgy perfectly conducting boundary by the corresponding interface filled with a dielectric material of extreme complex permittivities, is examined in the present work. A semi-analytical solution to the corresponding…

Classical Physics · Physics 2015-06-03 Constantinos A. Valagiannopoulos , Ari Sihvola

In this paper we analyze the gradient blow-up of the solution to the conductivity problem in two dimensions in the presence of an inclusion with eccentric core-shell geometry. Assuming that the core and shell have circular boundaries that…

Analysis of PDEs · Mathematics 2018-05-23 Junbeom Kim , Mikyoung Lim

The electric field increases toward infinity in the narrow region between closely adjacent perfect conductors as they approach each other. Much attention has been devoted to the blow-up estimate, especially in two dimensions, for the…

Analysis of PDEs · Mathematics 2008-09-01 Mikyoung Lim , KiHyun Yun

The paper establishes tight lower bound for effective conductivity tensor $K_*$ of two-dimensional three-phase conducting anisotropic composites and defines optimal microstructures. It is assumed that three materials are mixed with fixed…

Mathematical Physics · Physics 2024-04-19 Andrej Cherkaev , Yuan Zhang

Perfect light transmission into a dielectric at the Brewster angle is one of the simplest effects in macroscopic electromagnetism. The common wisdom states that absorption in the dielectric violates Brewster angle and leads to a…

Optics · Physics 2023-12-07 Valeria Maslova , Petr Lebedev , Denis G. Baranov

We study the insulated conductivity problem with closely spaced insulators embedded in a homogeneous matrix where the current-electric field relation is the power law $J = |E|^{p-2}E$. The gradient of solutions may blow up as $\varepsilon$,…

Analysis of PDEs · Mathematics 2023-05-12 Hongjie Dong , Zhuolun Yang , Hanye Zhu

The present study deals with total internal reflection of a plane electromagnetic wave at an infinite plane boundary between a transparent medium and an amplifying or attenuating lower-index medium. Solutions of Maxwell's equations are…

Optics · Physics 2023-06-13 Takeyuki Kobayashi

In this article, we consider the problem of finding the support of an inhomogenous possibly anisotropic inclusion in a background of constant electric conductivity from the electrical impedance tomography data at the boundary of a bounded…

Functional Analysis · Mathematics 2007-05-23 Erkki J. Somersalo

A conducting two-dimensional periodic composite of two anisotropic phases with anisotropic, not necessarily symmetric, conductivity tensors is considered. By finding approximate representations for the relevant operators, an approximation…

Mathematical Physics · Physics 2018-03-06 Graeme W. Milton

We consider the anisotropic Calderon problem of recovering a conductivity matrix or a Riemannian metric from electrical boundary measurements in three and higher dimensions. In the earlier work \cite{DKSaU}, it was shown that a metric in a…

Analysis of PDEs · Mathematics 2014-05-13 David Dos Santos Ferreira , Yaroslav Kurylev , Matti Lassas , Mikko Salo

The duality and other symmetry properties of the effective conductivity sigma_e of the classical two-dimensional isotropic randomly inhomogeneous heterophase systems at arbitrary number of phases N are discussed. A new approach for a…

Disordered Systems and Neural Networks · Physics 2007-05-23 S. A. Bulgadaev

This work concerns the design of perfectly conducting objects that are invisible to an incident transverse magnetic plane wave. The object in question is a finite planar waveguide with a finite periodic array of barriers. By optimizing this…

Computational Physics · Physics 2024-03-11 Johan Helsing , Shidong Jiang , Anders Karlsson

The inverse problem of electrical impedance tomography is severely ill-posed. In particular, the resolution of images produced by impedance tomography deteriorates as the distance from the measurement boundary increases. Such depth…

Analysis of PDEs · Mathematics 2020-04-21 Henrik Garde , Nuutti Hyvönen

We derive exact expressions for so-called ``void'' bounds on the trapping constant $\gamma$ and fluid permeability $k$ for coated-spheres and coated-cylinders models of porous media. We find that in some cases the bounds are optimal, i.e.,…

Soft Condensed Matter · Physics 2009-11-10 S. Torquato , D. C. Pham

We consider the initial-boundary value problem in the quarter space for the system of equations of ideal Magneto-Hydrodynamics for compressible fluids with perfectly conducting wall boundary conditions. On the two parts of the boundary the…

Analysis of PDEs · Mathematics 2024-11-20 Paolo Secchi

We present a ${\Gamma}$-convergence approximation for the total anisotropic length of a partition. This theoretical result gives rise to a numerical method which allows the study of minimal partitions with respect to different anisotropies.…

Optimization and Control · Mathematics 2016-09-07 Beniamin Bogosel

We compute cosmological perturbations for a generic self-gravitating media described by four derivatively- coupled scalar fields. Depending on the internal symmetries of the action for the scalar fields, one can describe perfect fluids,…

General Relativity and Quantum Cosmology · Physics 2017-11-28 Marco Celoria , Denis Comelli , Luigi Pilo

A model of an exact gravity dual of a gapless superconductor is presented in which the condensate is provided by a charged scalar field coupled to a bulk black hole of hyperbolic horizon in asymptotically AdS spacetime. Below a critical…

High Energy Physics - Theory · Physics 2009-07-22 George Koutsoumbas , Eleftherios Papantonopoulos , George Siopsis

We study the Einstein field equations for spacetimes admitting a maximal two-dimensional abelian group of isometries acting orthogonally transitively on spacelike surfaces and, in addition, with at least one conformal Killing vector. The…

General Relativity and Quantum Cosmology · Physics 2009-11-07 Marc Mars , Thomas Wolf

We are concerned with the quantitative study of the electric field perturbation due to the presence of an inhomogeneous conductive rod embedded in a homogenous conductivity. We sharply quantify the dependence of the perturbed electric field…

Analysis of PDEs · Mathematics 2020-09-09 Xiaoping Fang , Youjun Deng , Hongyu Liu