{
  "abstract": "Starting from a microscopic multiparticle Langevin equation, we obtain a hydrodynamic description in terms of density and momentum fields for chiral active particles interacting via standard repulsive and nonlocal odd forces. These odd interactions are reciprocal but non-conservative: they are non-potential forces, as they act perpendicular to the vector joining any pair of particles. As a result, the torques that two particles exert on one another are non-reciprocal. The ensuing macroscopic continuum description consists of a continuity equation for the density and a generalized compressible Navier–Stokes equation for the fluid velocity. The latter includes a chirality-induced torque density term and an odd viscosity contribution. Our theory predicts the emergence of odd diffusivity, edge currents, and is consistent with an inhomogeneous phase—characterized by bubble-like structures—recently observed in simulations. Specifically, the theory exhibits a linear instability arising from the interplay between odd viscosity and torque density, and admits steady-state inhomogeneous solutions featuring bubbles and vortices, in qualitative agreement with numerical simulations. Our findings can be tested experimentally in systems of granular spinners or rotating microorganisms suspended in a fluid.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2601.19432",
  "author_total": 4,
  "authors": [
    {
      "name": "Umberto Marini Bettolo Marconi"
    },
    {
      "name": "Alessandro Petrini"
    },
    {
      "name": "Raphael Maire"
    },
    {
      "name": "Lorenzo Caprini"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/bnz4e4kfpj92n.bib",
  "cited_by": 3,
  "doi": "10.1088/1367-2630/ae6c55",
  "fulltext_url": null,
  "id": "bnz4e4kfpj92n",
  "issns": [
    "1367-2630"
  ],
  "landing_url": "https://hal.science/hal-05853660v1",
  "language": "en",
  "licence": "CC-BY",
  "licence_label": "CC BY",
  "licence_source": "journal",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "hal",
      "0.phys"
    ],
    [
      "openalex",
      "3104|Micro and Nano Robotics"
    ]
  ],
  "openalex": "W7160917002",
  "pdf_url": null,
  "pmcid": null,
  "pmid": null,
  "published": "2026-11-05",
  "publisher": "Institute of Physics: Open Access Journals",
  "ris": "https://research.draconitic.com/paper/bnz4e4kfpj92n.ris",
  "sources": [
    {
      "first_seen": "2026-11-06T12:20:44Z",
      "native_id": "hal-05853660",
      "source": "hal",
      "url": "https://hal.science/hal-05853660v1"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "openalex:3104|Micro and Nano Robotics",
      "subfield": "condensed-matter"
    }
  ],
  "title": "Emergent hydrodynamics of chiral active fluids: vortices, bubbles and odd diffusion",
  "title_text": "Emergent hydrodynamics of chiral active fluids: vortices, bubbles and odd diffusion",
  "type": "peer-reviewed",
  "updated_at": "2026-11-07T12:20:25Z",
  "url": "https://research.draconitic.com/paper/bnz4e4kfpj92n",
  "venue": "New Journal of Physics",
  "versions": []
}