{
  "abstract": "A dual-alkali single-cell $^{87}$Rb-$^{39}$K-$^{3}$He comagnetometer can read an axion-like dark matter signal through two optical rotation channels, encoding the ratio $\\mathcal{R}=ξ_n/ξ_p$ of the field's neutron and proton spin couplings in their relative response. The inter-species phase difference $Δφ$ has been proposed as a calibration-free readout that is sensitive to $\\mathcal{R}$. Treating the extraction of $\\mathcal{R}$ as a statistical estimation problem, we show that the estimate of $\\mathcal{R}$ depends on the two channels only through their complex ratio, which splits into $Δφ$ and an amplitude ratio, of which only $Δφ$ is insensitive to the relative gain and hence calibration free. For our choice of comagnetometer parameters, above $\\sim\\!100$ Hz the phase difference alone captures most of the coupling-ratio information. At lower frequencies $Δφ$ is no longer near-sufficient. Below $\\sim\\!40$ Hz, the amplitude ratio would improve the precision on $\\mathcal{R}$ by a factor of $\\gtrsim2$. Recovering that information, however, requires the relative gain to be known sufficiently accurately, so $Δφ$ remains the robust observable even where it is not the most informative one.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": "Journal reference: Universe 2026, 12(10), 298",
  "arxiv": "2608.07456",
  "author_total": 6,
  "authors": [
    {
      "name": "Yossi Rosenzweig"
    },
    {
      "name": "Yevgeny Kats"
    },
    {
      "name": "Eli Sarid"
    },
    {
      "name": "Menachem Givon"
    },
    {
      "name": "Yonathan Japha"
    },
    {
      "name": "Ron Folman"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/1ys6zm1z9qk4f.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2608.07456",
  "fulltext_url": null,
  "id": "1ys6zm1z9qk4f",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2608.07456",
  "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",
      "hep-ph"
    ],
    [
      "arxiv",
      "physics.atom-ph"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2608.07456",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-09",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/1ys6zm1z9qk4f.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:28:36Z",
      "native_id": "2608.07456",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2608.07456"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:physics.atom-ph",
      "subfield": "amo"
    },
    {
      "field": "physics",
      "origin": "arxiv:hep-ph",
      "subfield": "high-energy"
    }
  ],
  "title": "Optimal Calibration-Free Observable for the Nucleon-Coupling Ratio in a Dual-Alkali Comagnetometer for Dark Matter Searches",
  "title_text": "Optimal Calibration-Free Observable for the Nucleon-Coupling Ratio in a Dual-Alkali Comagnetometer for Dark Matter Searches",
  "type": "preprint",
  "updated_at": "2026-10-30T12:28:36Z",
  "url": "https://research.draconitic.com/paper/1ys6zm1z9qk4f",
  "venue": "arXiv",
  "versions": [
    {
      "doi": "10.3390/universe12100298",
      "pid": null,
      "relation": "published-as",
      "title": null,
      "venue": null
    }
  ]
}