{
  "abstract": "One of the defining results in the study of active matter is the spontaneous flow instability, through which a homogeneous, uniformly aligned state breaks translational symmetry along a single direction and develops sustained flow. The vortex state that emerges at higher activity has instead been attributed to nonlinear dynamics. Using a Floquet-type linear stability analysis, we show that no such mechanism is required: the flowing state undergoes a secondary, zigzag instability that breaks the remaining translational symmetry and produces the vortex state. We further identify a regime in which the flowing state ceases to exist and vortices emerge directly from the uniformly aligned state. Under channel confinement, the instability selects a length scale that differs from the establishedactivelengthscale, andsetsthenumberofvorticesthatappear, leadingtoaconfinement- selected pattern reminiscent of a vortex lattice, opening a route toward direct experimental tests of this instability. Full nonlinear simulations reproduce the predicted onset activities and the selected vortex number.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.15093",
  "author_total": 3,
  "authors": [
    {
      "name": "Niels de Graaf Sousa"
    },
    {
      "name": "Kristian Thijssen"
    },
    {
      "name": "Amin Doostmohammadi"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/bv475twfxcdx4.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.15093",
  "fulltext_url": null,
  "id": "bv475twfxcdx4",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2609.15093",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "cond-mat.soft"
    ],
    [
      "openalex",
      "3104|Micro and Nano Robotics"
    ]
  ],
  "openalex": "W7213249633",
  "pdf_url": "https://arxiv.org/pdf/2609.15093",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-14",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/bv475twfxcdx4.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:21:25Z",
      "native_id": "2609.15093",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.15093"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:cond-mat.soft",
      "subfield": "condensed-matter"
    }
  ],
  "title": "Spontaneous Vortex Instability in Active Nematics",
  "title_text": "Spontaneous Vortex Instability in Active Nematics",
  "type": "preprint",
  "updated_at": "2026-10-30T12:21:25Z",
  "url": "https://research.draconitic.com/paper/bv475twfxcdx4",
  "venue": "arXiv",
  "versions": []
}