{
  "abstract": "Lowest-energy excitons are usually expected to have nodeless $1s$-like envelope wavefunctions. We show that band topology can obstruct this expectation. The exciton envelope wavefunction is a section of the valence-conduction transition bundle, whose topology can enforce momentum-space zeros, with their parity or signed total index fixed by the corresponding characteristic class. We exemplify this behavior in a minimal $PT$-symmetric three-band model with a rank-two transition bundle characterized by Euler number $ν^e=2$. By directly solving the Bethe-Salpeter equation with both contact and Rytova-Keldysh interactions, we find that the lowest exciton contains two zeros, each with index $+1$, and is less strongly bound than its topologically trivial counterpart. We further classify topology-enforced exciton nodal structures for real and complex transition bundles in dimensions $d \\leq 3$. Our results establish the topology of the transition bundle as a direct constraint on exciton wavefunctions and spectra.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.36248",
  "author_total": 1,
  "authors": [
    {
      "name": "Lumen Eek"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/6kw8ycr699wmj.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.36248",
  "fulltext_url": null,
  "id": "6kw8ycr699wmj",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2609.36248",
  "language": null,
  "licence": "LicenseRef-arXiv-nonexclusive-1.0",
  "licence_label": "arXiv licence",
  "licence_source": "article",
  "licence_url": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "cond-mat.mes-hall"
    ],
    [
      "openalex",
      "3107|Topological Materials and Phenomena"
    ]
  ],
  "openalex": "W7214960988",
  "pdf_url": "https://arxiv.org/pdf/2609.36248",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-28",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/6kw8ycr699wmj.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:25:31Z",
      "native_id": "2609.36248",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.36248"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:cond-mat.mes-hall",
      "subfield": "condensed-matter"
    }
  ],
  "title": "Topology Obstructs Nodeless Excitons",
  "title_text": "Topology Obstructs Nodeless Excitons",
  "type": "preprint",
  "updated_at": "2026-10-30T12:25:31Z",
  "url": "https://research.draconitic.com/paper/6kw8ycr699wmj",
  "venue": "arXiv",
  "versions": []
}