{
  "abstract": "We find the optimal initial states of a linearized cavity-optomechanical system for estimating the single-photon coupling by quantum Fisher information. In the red-detuned (beam-splitter) regime the interaction exchanges excitations between the two modes, and for pure inputs the Fisher information is four times the variance of the excitation-exchange operator, reducing the optimization to variance maximization with a closed-form solution. With the mechanical mode in a Fock state the probe is degenerate: any state saturating the photon-number constraint is optimal, and a Fock reference with many phonons enhances the per-photon sensitivity linearly. For an arbitrary fixed mechanical reference it becomes a phase-matched squeezed vacuum, from an exact bound on that coherence obtained by a Lagrange-dual argument. Jointly optimizing both modes at fixed total excitation number, the quantum Fisher information obeys a Heisenberg bound quadratic in the energy, saturated by equal superpositions of the two extremal eigenstates of the generator, equivalently a two-mode NOON state after a balanced beam splitter; balanced product Fock states reach only a linear enhancement. Exact diagonalization in truncated Fock spaces confirms all the results, the familiar single-photon input being the simplest saturating case. Three extensions are worked out: the blue sideband has an unbounded two-mode-squeezing spectrum, so the entangled optimum becomes impossible and the balanced product Fock state is exactly optimal at definite energy; under cavity loss the information accumulation turns linear on the cavity-lifetime timescale, at a renewal-optimal duration of about two and a half lifetimes; and for a state-of-the-art quantum-coherent coupling experiment the per-hour relative precision lies between one part in a million and ten parts in a million, number and thermal references being the most robust.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.01417",
  "author_total": 7,
  "authors": [
    {
      "name": "Wangjun Lu"
    },
    {
      "name": "Qing Yu"
    },
    {
      "name": "Ying Li"
    },
    {
      "name": "Cuilu Zhai"
    },
    {
      "name": "Rui Zhang"
    },
    {
      "name": "Zhao-Hui Peng"
    },
    {
      "name": "Shiqing Tang"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/8641jwqpn0yzy.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.01417",
  "fulltext_url": null,
  "id": "8641jwqpn0yzy",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.01417",
  "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",
      "3107|Mechanical and Optical Resonators"
    ]
  ],
  "openalex": "W7216389318",
  "pdf_url": "https://arxiv.org/pdf/2610.01417",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-01",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/8641jwqpn0yzy.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:26:03Z",
      "native_id": "2610.01417",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.01417"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:quant-ph",
      "subfield": "quantum"
    }
  ],
  "title": "Optimal initial states for quantum Fisher information in linearized cavity optomechanics",
  "title_text": "Optimal initial states for quantum Fisher information in linearized cavity optomechanics",
  "type": "preprint",
  "updated_at": "2026-10-30T12:26:03Z",
  "url": "https://research.draconitic.com/paper/8641jwqpn0yzy",
  "venue": "arXiv",
  "versions": []
}