{
  "abstract": "For non-Hermitian Hamiltonians, gain, loss, and non-reciprocity produce complex eigenvalues which, in turn, facilitate different kinds of topological phases. One example is the imaginary line-gap phase, where eigenvalues cannot lie on the real line. This notion was recently shown to explain the robust temporal localisation of waves in photonic quantum walks and time-varying metamaterials. In these systems, waves localise around a time interface between topologically inequivalent mediums. At the core of this phenomenon is a $\\mathcal{PT}$-symmetric two-mode model, where the non-trivial topology arises due to the $\\mathbb{Z}_2$ classification of the AI symmetry class. In this work, we study two-mode models in all non-Hermitian symmetry classes. We find that robust temporal localisation generically follows as a physical consequence of imaginary line-gap topology according to a simple diagnostic: at least one of time-reversal symmetry ($\\mathcal{T}^{\\hspace{0.05em}2} = 1$) and particle-hole symmetry ($\\mathcal{C}^2 = 1$) must be present. Our results provide a comprehensive symmetry-based guide to the observation of the topologically protected temporal localisation of waves.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.11577",
  "author_total": 7,
  "authors": [
    {
      "name": "Carlos Camacho"
    },
    {
      "name": "Tom Sheppard"
    },
    {
      "name": "Joshua Feis"
    },
    {
      "name": "Oliver Ashfield"
    },
    {
      "name": "Alexander Szameit"
    },
    {
      "name": "Frank Schindler"
    },
    {
      "name": "Hannah M. Price"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/7qtnrp3x608q8.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.11577",
  "fulltext_url": null,
  "id": "7qtnrp3x608q8",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2609.11577",
  "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",
      "physics.optics"
    ],
    [
      "openalex",
      "3107|Quantum Mechanics and Non-Hermitian Physics"
    ]
  ],
  "openalex": "W7212294449",
  "pdf_url": "https://arxiv.org/pdf/2609.11577",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-11",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/7qtnrp3x608q8.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:21:25Z",
      "native_id": "2609.11577",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.11577"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:physics.optics",
      "subfield": "optics-photonics"
    }
  ],
  "title": "Temporal Localisation of Waves from Imaginary Line-Gap Topology",
  "title_text": "Temporal Localisation of Waves from Imaginary Line-Gap Topology",
  "type": "preprint",
  "updated_at": "2026-10-30T12:21:25Z",
  "url": "https://research.draconitic.com/paper/7qtnrp3x608q8",
  "venue": "arXiv",
  "versions": []
}