{
  "abstract": "We study the band structure of evanescent waves, that is, the decaying or growing solutions that live within the gaps of tight-binding Hamiltonians. Although the underlying Hamiltonian is Hermitian, these modes carry complex wavevectors and therefore exhibit a non-Hermitian dispersion. Using the transfer matrix formalism in one dimension, we show that, in addition to the standard exceptional points that appear at the band edges, a different type of exceptional point can arise inside the gap, protected by spinless time-reversal symmetry. Tuning model parameters drives a topological transition where such in-gap exceptional points are nucleated in pairs, mediated by a crossing between purely imaginary momentum branches. We show that this spectral structure is diagnosed by a $\\mathbb{Z}_2$ index assigned to every energy inside the gap, with the in-gap exceptional points arising as its domain walls. A generic bound state in the system has a tail that is purely exponential when its energy lies between a band edge and the nearest exceptional point, but becomes oscillatory - with a wavevector differing from the band-edge momentum - when its energy lies between the pair of in-gap exceptional points. We illustrate these results using continuum and tight-binding models, as well as an anisotropic photonic crystal.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2611.07038",
  "author_total": 5,
  "authors": [
    {
      "name": "Ignacio Pavez"
    },
    {
      "name": "Tom Sheppard"
    },
    {
      "name": "Yoonseok Hwang"
    },
    {
      "name": "Hannah M. Price"
    },
    {
      "name": "Frank Schindler"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/412d7hz6n502q.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2611.07038",
  "fulltext_url": null,
  "id": "412d7hz6n502q",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2611.07038",
  "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"
    ],
    [
      "arxiv",
      "physics.optics"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2611.07038",
  "pmcid": null,
  "pmid": null,
  "published": "2026-11-04",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/412d7hz6n502q.ris",
  "sources": [
    {
      "first_seen": "2026-11-06T18:21:30Z",
      "native_id": "2611.07038",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2611.07038"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:cond-mat.mes-hall",
      "subfield": "condensed-matter"
    },
    {
      "field": "physics",
      "origin": "arxiv:physics.optics",
      "subfield": "optics-photonics"
    }
  ],
  "title": "Topological Transitions of Evanescent Waves",
  "title_text": "Topological Transitions of Evanescent Waves",
  "type": "preprint",
  "updated_at": "2026-11-09T00:20:40Z",
  "url": "https://research.draconitic.com/paper/412d7hz6n502q",
  "venue": "arXiv",
  "versions": []
}