{
  "abstract": "For local hidden-variable accounts of the CHSH experiment that are faithful -- reproducing the observed singles and coincidence rates and unbiased marginals of a polarization singlet with symmetric detector efficiency $η_{\\rm eff}$ -- I determine the minimal measurement dependence $M$ (Hall's measure) needed to reach a CHSH value $S$. Linear programming over all local strategies yields $M(S,η_{\\rm eff})=\\max\\{0,η_{\\rm eff}((S+2)η_{\\rm eff}-4)/6\\}$, whose edges reproduce Hall's bound, the Garg-Mermin threshold, and the postselection ceiling. The quantum point is certified exactly: $M(2\\sqrt{2},9/10)=(27\\sqrt{2}-33)/100$, by primal and dual certificates in $\\mathbb{Q}(\\sqrt{2})$. I solve the detection profile under which a deterministic sign model reproduces the singlet exactly, and prove exact quantum correlations and angle-independent coincidence rates jointly impossible in this class. Mixtures of this profile with measurement dependence trade $M$ against a $\\cos 4(a-b)$ modulation of the fourfold coincidence sum, up to 12.4% in relative amplitude, identical at the two CHSH angles; existing data exclude its full amplitude and bound its mixtures with flat detection to a detection share of order 15%; its sub-percent content is unbounded. A two-setting cross-ratio and a settings-torus log-Fourier protocol, calibrated against channel-efficiency imbalance, reach $5σ$ at 0.1% within hours; a flat result excludes the solved family to a detection share of order 1%. A local mechanism, moiré phase locking, with deterministic phase evolution and quenched randomness, attains the certified floor exactly at $η_{\\rm eff}=1$ and, with the solved profile, reaches $M=0$ at $η_{\\rm eff}\\approx 0.80$. Its floor-attaining census shares a low-order Fourier skeleton across independent solutions and is not realizable by station-local offsets on the terrains tested.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2608.18886",
  "author_total": 1,
  "authors": [
    {
      "name": "Aaron Alai"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/9w4dners9qqxc.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2608.18886",
  "fulltext_url": null,
  "id": "9w4dners9qqxc",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2608.18886",
  "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",
      "quant-ph"
    ],
    [
      "openalex",
      "3107|Quantum Mechanics and Applications"
    ]
  ],
  "openalex": "W7203929847",
  "pdf_url": "https://arxiv.org/pdf/2608.18886",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-28",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/9w4dners9qqxc.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:36:22Z",
      "native_id": "2608.18886",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2608.18886"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:quant-ph",
      "subfield": "quantum"
    }
  ],
  "title": "The exact price of local realism in CHSH experiments: a measurement-dependence-detection trade-off surface, a moiré phase-locking mechanism that saturates it, and an unmeasured fringe in the fourfold coincidence sum",
  "title_text": "The exact price of local realism in CHSH experiments: a measurement-dependence-detection trade-off surface, a moiré phase-locking mechanism that saturates it, and an unmeasured fringe in the fourfold coincidence sum",
  "type": "preprint",
  "updated_at": "2026-11-01T12:20:44Z",
  "url": "https://research.draconitic.com/paper/9w4dners9qqxc",
  "venue": "arXiv",
  "versions": []
}