A dynamical systems approach to WKB-methods: The eigenvalue problem for a single well potential

Fuente: arXiv
Saved in:
Bibliographic Details
Main Authors: Kristiansen, Kristian Uldall, Szmolyan, Peter
Format: Preprint
Published: 2025
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866913986848489472
author Kristiansen, Kristian Uldall
Szmolyan, Peter
author_facet Kristiansen, Kristian Uldall
Szmolyan, Peter
contents In this paper, we revisit the eigenvalue problem of the one-dimensional Schr{ö}dinger equation for smooth single well potentials. In particular, we provide a new interpretation of the Bohr-Sommerfeld quantization formula. A novel aspect of our results, which are based on recent work of the authors on the turning point problem based upon dynamical systems methods, is that we cover all eigenvalues $E\in [0,\mathcal O(1)]$ and show that the Bohr-Sommerfeld quantitization formula approximates all of these eigenvalues (in a sense that is made precise). At the same time, we provide rigorous smoothness statements of the eigenvalues as functions of $ε$. We find that whereas the small eigenvalues $E=\mathcal O(ε)$ are smooth functions of $ε$, the large ones $E=\mathcal O(1)$ are smooth functions of $nε\in[c_1,c_2],\,0<c_1<c_2<\infty$, and $0\le ε^{1/3}\ll 1$; here $n\in \mathbb N_0$ is the index of the eigenvalues.
format Preprint
id arxiv_https___arxiv_org_abs_2501_10707
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle A dynamical systems approach to WKB-methods: The eigenvalue problem for a single well potential
Kristiansen, Kristian Uldall
Szmolyan, Peter
Mathematical Physics
Dynamical Systems
Spectral Theory
In this paper, we revisit the eigenvalue problem of the one-dimensional Schr{ö}dinger equation for smooth single well potentials. In particular, we provide a new interpretation of the Bohr-Sommerfeld quantization formula. A novel aspect of our results, which are based on recent work of the authors on the turning point problem based upon dynamical systems methods, is that we cover all eigenvalues $E\in [0,\mathcal O(1)]$ and show that the Bohr-Sommerfeld quantitization formula approximates all of these eigenvalues (in a sense that is made precise). At the same time, we provide rigorous smoothness statements of the eigenvalues as functions of $ε$. We find that whereas the small eigenvalues $E=\mathcal O(ε)$ are smooth functions of $ε$, the large ones $E=\mathcal O(1)$ are smooth functions of $nε\in[c_1,c_2],\,0<c_1<c_2<\infty$, and $0\le ε^{1/3}\ll 1$; here $n\in \mathbb N_0$ is the index of the eigenvalues.
title A dynamical systems approach to WKB-methods: The eigenvalue problem for a single well potential
topic Mathematical Physics
Dynamical Systems
Spectral Theory
url https://arxiv.org/abs/2501.10707