Sturm-Hurwitz Theorem for quantum graphs
Mathematical Physics
2023-10-09 v1 math.MP
Spectral Theory
Abstract
We prove upper and lower bounds for the number of zeroes of linear combinations of Schr\"odinger eigenfunctions on metric (quantum) graphs. These bounds are distinct from both the interval and manifolds. We complement these bounds by giving non-trivial examples for the lower bound as well as sharp examples for the upper bound. In particular, we show that even tree graphs differ from the interval with respect to the nodal count of linear combinations of eigenfunctions. This stands in distinction to previous results which show that all tree graphs have to same eigenfunction nodal count as the interval.
Keywords
Cite
@article{arxiv.2310.03877,
title = {Sturm-Hurwitz Theorem for quantum graphs},
author = {Ram Band and Philippe Charron},
journal= {arXiv preprint arXiv:2310.03877},
year = {2023}
}