{
  "abstract": "Device-independent conference key agreement (DI-CKA) enables $N > 2$ distant parties to establish a common secret key without detailed characterization of the source or measurement devices. Many existing protocols rely on full-body Bell correlators, whose measurement can be demanding for a large number of parties. Here, we show that two-body correlators alone suffice for DI-CKA using balanced Dicke states for every even $N \\geq 4$. We construct two-body Bell inequalities and derive a tight analytical lower bound on the conditional von Neumann entropy by comparing their Bell operators with those of asymmetric Clauser-Horne-Shimony-Holt inequalities. In the ideal setting, certified key rates can approach $1-h[(N-2)/(4(N-1))]$, where $h$ is the binary entropy function. This rate remains bounded away from zero as $N \\rightarrow \\infty$, tending to $1-h(1/4) \\approx 0.189$ bits per key-generation round. We show that the honest implementation of our protocol is invariant under collective phase noise. Moreover, a complementary full-body Bell construction certifies positive conference-key rates from correlations arbitrarily close to the local set.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.41712",
  "author_total": 2,
  "authors": [
    {
      "name": "Makoto Ishihara"
    },
    {
      "name": "Masahiro Takeoka"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/17vzjkzdf4crh.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.41712",
  "fulltext_url": null,
  "id": "17vzjkzdf4crh",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.41712",
  "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",
      "quant-ph"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2610.41712",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-30",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/17vzjkzdf4crh.ris",
  "sources": [
    {
      "first_seen": "2026-11-02T12:21:15Z",
      "native_id": "2610.41712",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.41712"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:quant-ph",
      "subfield": "quantum"
    }
  ],
  "title": "Device-independent conference key agreement from two-body correlators with balanced Dicke states",
  "title_text": "Device-independent conference key agreement from two-body correlators with balanced Dicke states",
  "type": "preprint",
  "updated_at": "2026-11-04T15:20:51Z",
  "url": "https://research.draconitic.com/paper/17vzjkzdf4crh",
  "venue": "arXiv",
  "versions": []
}