Salvato in:
| Autore principale: | |
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| Natura: | Preprint |
| Pubblicazione: |
2025
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| Soggetti: | |
| Accesso online: | https://arxiv.org/abs/2509.20320 |
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Sommario:
- We discuss spectral properties of the one-dimensional Schrödinger operator with a potential of the form $\sum V(n)δ(x-n)$. Our main result says that the absolutely continuous spectum of such an operator covers an interval $[α^2,β^2]$, if $V\in \ell^4$ and the Fourier series $\sum e^{2i kn}V(n)$ is a function of $k$ that is square integrable over $[α,β]$. We prove that this result is sharp by constructing examples of potentials $V\notin\ell^2$ for which the spectrum of the Schrödinger operator is singular.