Transmission Eigenvalues and Non-scattering
Abstract
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 survey deals with the so-called transmission spectrum, namely those wave numbers at which non-scattering potentially may occur. For wave numbers that are not transmission eigenvalues any incident wave leads to scattering, however, being at a transmission eigenvalue is far from su!cient to guarantee the occurence of non-scattering for even a single incident wave. For instance the inhomogeneity generically has to be smooth for non-scattering to occur. Similarly many smooth geometric shapes will be scattering for natural incident waves even at a transmission eigenvalue. Part of the survey discusses recent results of that nature.
Cite
@article{arxiv.2602.06250,
title = {Transmission Eigenvalues and Non-scattering},
author = {Fioralba Cakoni and Michael S. Vogelius},
journal= {arXiv preprint arXiv:2602.06250},
year = {2026}
}