Optimizing the Fundamental Eigenvalue Gap of Quantum Graphs

Fuente: arXiv
Saved in:
Bibliographic Details
Main Authors: Ahrami, Mohammed, Allali, Zakaria El, Harrell II, Evans M, Kennedy, James B.
Format: Preprint
Published: 2024
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866911751469006848
author Ahrami, Mohammed
Allali, Zakaria El
Harrell II, Evans M
Kennedy, James B.
author_facet Ahrami, Mohammed
Allali, Zakaria El
Harrell II, Evans M
Kennedy, James B.
contents We study the problem of minimizing or maximizing the fundamental spectral gap of Schrödinger operators on metric graphs with either a convex potential or a ``single-well'' potential on an appropriate specified subset. (In the case of metric trees, such a subset can be the entire graph.) In the convex case we find that the minimizing and maximizing potentials are piecewise linear with only a finite number of points of non-smoothness, but give examples showing that the optimal potentials need not be constant. This is a significant departure from the usual scenarios on intervals and domains where the constant potential is typically minimizing. In the single-well case we show that the optimal potentials are piecewise constant with a finite number of jumps, and in both cases give an explicit estimate on the number of points of non-smoothness, respectively jumps, the minimizing potential can have. Furthermore, we show that, unlike on domains, it is not generally possible to find nontrivial bounds on the fundamental gap in terms of the diameter of the graph alone, within the given classes.
format Preprint
id arxiv_https___arxiv_org_abs_2401_04344
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Optimizing the Fundamental Eigenvalue Gap of Quantum Graphs
Ahrami, Mohammed
Allali, Zakaria El
Harrell II, Evans M
Kennedy, James B.
Spectral Theory
34B45, 34L15, 35J05, 81Q35
We study the problem of minimizing or maximizing the fundamental spectral gap of Schrödinger operators on metric graphs with either a convex potential or a ``single-well'' potential on an appropriate specified subset. (In the case of metric trees, such a subset can be the entire graph.) In the convex case we find that the minimizing and maximizing potentials are piecewise linear with only a finite number of points of non-smoothness, but give examples showing that the optimal potentials need not be constant. This is a significant departure from the usual scenarios on intervals and domains where the constant potential is typically minimizing. In the single-well case we show that the optimal potentials are piecewise constant with a finite number of jumps, and in both cases give an explicit estimate on the number of points of non-smoothness, respectively jumps, the minimizing potential can have. Furthermore, we show that, unlike on domains, it is not generally possible to find nontrivial bounds on the fundamental gap in terms of the diameter of the graph alone, within the given classes.
title Optimizing the Fundamental Eigenvalue Gap of Quantum Graphs
topic Spectral Theory
34B45, 34L15, 35J05, 81Q35
url https://arxiv.org/abs/2401.04344