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This paper deals with the numerical study of a strongly anisotropic heat equation. The use of standard schemes in this situation leads to poor results, due to the high anisotropy. Furthermore, the recently proposed Asymptotic-Preserving…

Numerical Analysis · Mathematics 2015-06-15 Jacek Narski , Maurizio Ottaviani

We demonstrate that a periodic waveguide comprising of uniform lossless segments together with discrete gain and radiating elements supports exceptional points of degeneracy (EPDs). We provide analytical expressions for all possible…

Applied Physics · Physics 2021-06-16 Ahmed F. Abdelshafy , Tarek Mealy , Ehsan Hafezi , Alireza Nikzamir , Filippo Capolino

We consider locally stabilized, conforming finite element schemes on completely unstructured simplicial space-time meshes for the numerical solution of parabolic initial-boundary value problems with variable, possibly discontinuous in space…

Numerical Analysis · Mathematics 2020-03-23 Ulrich Langer , Andreas Schafelner

We are concerned with global weak solutions to the isentropic compressible Euler equations with cylindrically symmetric rotating structure, in which the origin is included. Due to the presence of the singularity at the origin, only the case…

Analysis of PDEs · Mathematics 2020-06-03 Difan Yuan

We study the asymptotic properties of the small data solutions of the Vlasov-Maxwell system in dimension three. No neutral hypothesis nor compact support assumptions are made on the data. In particular, the initial decay in the velocity…

Analysis of PDEs · Mathematics 2020-07-07 Léo Bigorgne

We demonstrate that the reformulation of renormalization group (RG) flow equations as non-linear heat equations has severe implications on the understanding of RG flows in general. We demonstrate by explicitly constructing an entropy…

Statistical Mechanics · Physics 2022-09-16 Adrian Koenigstein , Martin J. Steil , Nicolas Wink , Eduardo Grossi , Jens Braun

We present an alternative representation for the anisotropic Eliashberg equations of superconductivity, whose numerical solution yields an efficiency gain of several orders of magnitude with respect to the conventional representation in…

Superconductivity · Physics 2020-10-15 Jon Lafuente-Bartolome , Idoia G. Gurtubay , Asier Eiguren

We develop a high order accurate numerical method for solving the elastic wave equation in second-order form. We hybridize the computationally efficient Cartesian grid formulation of finite differences with geometrically flexible…

Numerical Analysis · Mathematics 2025-02-04 Andreas Granath , Siyang Wang

We focus on non-stationary Maxwell equations defined on a regular patch of elements as considered in the isogeometric analysis (IGA). We apply the time-integration scheme following the ideas developed by the finite difference community [M.…

Numerical Analysis · Mathematics 2021-07-20 Maciej Paszynski , Marcin Los , Judit Munoz-Matute

Using soft-graviton theorems a well-known zero-frequency limit (ZFL) for the gravitational radiation flux $dE^{GW}/d \omega$ is re-derived and extended to order ${{\cal O}}(\omega)$ and ${{\cal O}}(\omega^2)$ for arbitrary massless…

High Energy Physics - Theory · Physics 2019-06-05 Andrea Addazi , Massimo Bianchi , Gabriele Veneziano

This study presents a finite difference method (FDM) to model the electromagnetic field propagation in eccentric coaxial waveguides filled with lossy uniaxially anisotropic media. The formulation utilizes conformal transformation to map the…

Computational Engineering, Finance, and Science · Computer Science 2025-01-24 Raul O. Ribeiro , Maria A. Martinez , Guilherme S. Rosa , Rafael A. Penchel

We investigate the Exact Renormalization Group (ERG) description of ($Z_2$ invariant) one-component scalar field theory, in the approximation in which all momentum dependence is discarded in the effective vertices. In this context we show…

High Energy Physics - Theory · Physics 2009-10-28 Tim R. Morris

In this paper the finite-difference time-domain general vector auxiliary differential equation method [Greene, J. H. and A. Taflove, Opt. Express 14, 8305 (2006)], nonlinear polarization vector, the nonlinear electric dipole moment per unit…

Optics · Physics 2025-09-10 Caleb J. Grimms , Robert D. Nevels

The chase of universal bounds on diffusivities in strongly coupled systems and holographic models has a long track record. The identification of a universal velocity scale, independent of the presence of well-defined quasiparticle…

High Energy Physics - Theory · Physics 2021-05-10 Ning Wu , Matteo Baggioli , Wei-Jia Li

This article presents an ultraweak discontinuous Petrov-Galerkin (DPG) formulation of the time-harmonic Maxwell equations for the vectorial envelope of the electromagnetic field in a weakly-guiding multi-mode fiber waveguide. This…

Numerical Analysis · Mathematics 2024-11-15 Stefan Henneking , Jacob Grosek , Leszek Demkowicz

We present predictions for the flow of elastoviscoplastic (EVP) fluids in the 4 to 1 planar contraction geometry. The Saramito-Herschel-Bulkley fluid model is solved via the finite-volume method with the OpenFOAM software. Both the…

Fluid Dynamics · Physics 2024-03-19 Milad Mousavi , Yannis Dimakopoulos , John Tsamopoulos

This paper is concerned with a conceptual gesture-based instruction/input technique using electromagnetic wave detection. The gestures are modelled as the shapes of some impenetrable or penetrable scatterers from a certain admissible class,…

Analysis of PDEs · Mathematics 2017-08-10 Jingzhi Li , Hongyu Liu , Hongpeng Sun

In this paper, we study the Lie point symmetry group of a system describing an ideal plastic plane flow in two dimensions in order to find analytical solutions of the system. The infinitesimal generators that span the Lie algebra for this…

Mathematical Physics · Physics 2015-06-03 Vincent Lamothe

This paper presents a method for extraction and analysis of curve--type structures which consist of disconnected components. Such structures are found in electron--microscopy (EM) images of metal nanograins, which are widely used in the…

Graphics · Computer Science 2013-12-02 P. Spurek , A. Chaikouskaya , J. Tabor , E. Zając

A typical singularity of elastic wave propagation, often termed a shear-wave singularity, takes place when the Christoffel equation has a double root or, equivalently, two out of three slowness or phase-velocity sheets share a common point.…

Geophysics · Physics 2019-07-16 Vladimir Grechka