{
  "abstract": "Active particles confined in droplets can set their host droplet into motion. This phenomenon is usually attributed to direct hydrodynamic forcing by the enclosed particles. Here we reveal a different mechanism: we show that a self-propelled raft of active colloids confined in a thin oil droplet at the surface of water typically follows an off-centered orbit, thus periodically deforming the droplet's contact line in an anisotropic way. This non-reciprocal deformation acts as a swimming stroke and propels the droplet according to the principles of low-Reynolds-number swimming. The effect is absent for a single colloid and arises from the intrinsically many-body dynamics of the raft, which we capture with a dynamical model coupling viscous hydrodynamics and many-body active dynamics. Our results show how collective internal activity can be converted into locomotion through deformation of a soft confining boundary.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.21963",
  "author_total": 6,
  "authors": [
    {
      "name": "Airi N. Kato"
    },
    {
      "name": "Julien Brémont"
    },
    {
      "name": "Etienne Harté"
    },
    {
      "name": "Jean-Michel Rampnoux"
    },
    {
      "name": "Jean-François Joanny"
    },
    {
      "name": "Hamid Kellay"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/9thgyf7eygbh0.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.21963",
  "fulltext_url": null,
  "id": "9thgyf7eygbh0",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2609.21963",
  "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.soft"
    ],
    [
      "arxiv",
      "physics.flu-dyn"
    ],
    [
      "openalex",
      "3104|Micro and Nano Robotics"
    ]
  ],
  "openalex": "W7213918823",
  "pdf_url": "https://arxiv.org/pdf/2609.21963",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-18",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/9thgyf7eygbh0.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:23:03Z",
      "native_id": "2609.21963",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.21963"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:cond-mat.soft",
      "subfield": "condensed-matter"
    },
    {
      "field": "physics",
      "origin": "arxiv:physics.flu-dyn",
      "subfield": "fluid-dynamics"
    }
  ],
  "title": "Active colloidal rafts perform swimming strokes that propel their host droplets",
  "title_text": "Active colloidal rafts perform swimming strokes that propel their host droplets",
  "type": "preprint",
  "updated_at": "2026-10-30T12:23:03Z",
  "url": "https://research.draconitic.com/paper/9thgyf7eygbh0",
  "venue": "arXiv",
  "versions": []
}