# Gaps in the spectrum of two-dimensional square packing of stiff disks

Research paper by L. D'Elia, S. A. Nazarov

Indexed on: 16 Nov '20Published on: 13 Nov '20Published in: arXiv - Mathematics - Analysis of PDEs

#### Abstract

In this paper we investigate via an asymptotic method the opening of gaps in the spectrum of a stiff problem for the Laplace operator $-\Delta$ in $\mathbb{R}^2$ perforated by contiguous circular holes. The density and the stiffness constants are of order $\varepsilon^{-2m}$ and $\varepsilon^{-1}$ in the holes with $m\in (0,1/2)$. We provide an explicit expression of the leading terms of the eigenvalues and the corresponding eigenfunctions which are related to the Bessel functions of the first kind.