{
  "abstract": "Bound states in the continuum (BICs) exhibit rich momentum-space dynamics, including merging, annihilation, and reconnection across symmetry directions and bands. Yet these phenomena have largely been explained case by case, without a unified framework to classify or predict them. Here we develop a global symmetry-equivariant theory for the dynamics of nondegenerate and degenerate BICs. We show that BIC dynamics can be classified into $α$-, $β$-, and $γ$-processes according to root motion, which not only encompass the reported dynamics in $C_{2v}$, $C_{4v}$, and $C_{6v}$ systems but also include previously unrecognized ones. More importantly, we reveal that distinct dynamics are bridged by the criticality of BICs through a \\emph{merging of merging}, in which selected direction--band branches acquire higher-order radiation zeros. Such a theory predicts which branches become critical and how to tune system parameters to realize them. Following this framework, we construct high-order BICs in full-wave calculations, realizing $Q\\sim k^{-10}$ nondegenerate criticality and $Q\\sim k^{-8}$ single-branch and band-paired degenerate criticalities. Our framework provides a systematic route to understanding, discovering, and selectively controlling BIC dynamics and high-$Q$ states.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.28934",
  "author_total": 3,
  "authors": [
    {
      "name": "Keren Wang"
    },
    {
      "name": "Lujun Huang"
    },
    {
      "name": "Wei Wang"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/9czgtej9hnwb2.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.28934",
  "fulltext_url": null,
  "id": "9czgtej9hnwb2",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2609.28934",
  "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",
      "2504|Metamaterials and Metasurfaces Applications"
    ]
  ],
  "openalex": "W7214308482",
  "pdf_url": "https://arxiv.org/pdf/2609.28934",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-24",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/9czgtej9hnwb2.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:24:11Z",
      "native_id": "2609.28934",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.28934"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:physics.optics",
      "subfield": "optics-photonics"
    }
  ],
  "title": "Global Framework for Dynamics and Criticality of Bound States in the Continuum",
  "title_text": "Global Framework for Dynamics and Criticality of Bound States in the Continuum",
  "type": "preprint",
  "updated_at": "2026-10-30T12:24:11Z",
  "url": "https://research.draconitic.com/paper/9czgtej9hnwb2",
  "venue": "arXiv",
  "versions": []
}