{ "id": "1910.04905", "version": "v1", "published": "2019-10-10T23:15:03.000Z", "updated": "2019-10-10T23:15:03.000Z", "title": "Localization of the first eigenfunction of a convex domain", "authors": [ "Thomas Beck" ], "categories": [ "math.AP", "math.SP" ], "abstract": "We study the first Dirichlet eigenfunction of the Laplacian in a $n$-dimensional convex domain. For domains of a fixed inner radius, estimates of Chiti imply that the ratio of the $L^2$-norm and $L^{\\infty}$-norm of the eigenfunction is minimized when the domain is a ball. However, when the eccentricity of the domain is large the eigenfunction should spread out at a certain scale and this ratio should increase. We make this precise by obtaining a lower bound on the $L^2$-norm of the eigenfunction and show that the eigenfunction cannot localize to too small a subset of the domain. As a consequence, we settle a conjecture of van den Berg, in the general $n$-dimensional case. The main feature of the proof is to obtain sufficiently sharp estimates on the first eigenvalue in order to estimate the first derivatives of the eigenfunction.", "revisions": [ { "version": "v1", "updated": "2019-10-10T23:15:03.000Z" } ], "analyses": { "keywords": [ "first eigenfunction", "localization", "first dirichlet eigenfunction", "van den berg", "dimensional convex domain" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }