1-D Schrödinger operator on a star graph with nondefinite weight function

Fuente: arXiv
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Main Authors: Leguizamón, Edison, Trunk, Carsten, Wilson, Mitsuru, Winklmeier, Monika
Format: Preprint
Published: 2025
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author Leguizamón, Edison
Trunk, Carsten
Wilson, Mitsuru
Winklmeier, Monika
author_facet Leguizamón, Edison
Trunk, Carsten
Wilson, Mitsuru
Winklmeier, Monika
contents On a star graph $G$ with $n = n_+ + n_-$ edges of unit length, we study the operator $-\frac{\mathrm{d}^2}{\mathrm{d} x^2}$ on $n_+$ and $\frac{\mathrm{d}^2}{\mathrm{d} x^2}$ on $n_-$ edges equipped with Dirichlet boundary conditions at the outer vertices and a Kirchhoff condition at the central vertex. We study the spectral properties of the corresponding indefinite Kirchhoff Laplacian on $G$ and we show that it is similar to a selfadjoint operator in the Hilbert space $L^2(G)$ and that its eigenfunctions form a Riesz basis. Furthermore, we give a complete description of the point spectrum.
format Preprint
id arxiv_https___arxiv_org_abs_2505_22901
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle 1-D Schrödinger operator on a star graph with nondefinite weight function
Leguizamón, Edison
Trunk, Carsten
Wilson, Mitsuru
Winklmeier, Monika
Spectral Theory
47A10, 47A75, 34B45
On a star graph $G$ with $n = n_+ + n_-$ edges of unit length, we study the operator $-\frac{\mathrm{d}^2}{\mathrm{d} x^2}$ on $n_+$ and $\frac{\mathrm{d}^2}{\mathrm{d} x^2}$ on $n_-$ edges equipped with Dirichlet boundary conditions at the outer vertices and a Kirchhoff condition at the central vertex. We study the spectral properties of the corresponding indefinite Kirchhoff Laplacian on $G$ and we show that it is similar to a selfadjoint operator in the Hilbert space $L^2(G)$ and that its eigenfunctions form a Riesz basis. Furthermore, we give a complete description of the point spectrum.
title 1-D Schrödinger operator on a star graph with nondefinite weight function
topic Spectral Theory
47A10, 47A75, 34B45
url https://arxiv.org/abs/2505.22901