{
  "abstract": "We present a protocol for simultaneous estimation of both quadratures of a displacement channel on a quantum harmonic oscillator using a single ancilla qubit, without complex state preparation or adaptive control. The qubit is coupled to the quantum harmonic oscillator via controlled displacements of strength $A$ and undergoes $N$ rounds of measurement and reset, while the oscillator coherently accumulates the displacement signal. The non-commuting displacements imprint an order-dependent geometric phase at each round, giving a quantum Fisher information that scales as $\\mathcal{O}(A^{2} N^{3})$. Although the measurement record space grows as $2^N$, we show that exact likelihoods for any individual measurement record can be computed in $\\mathcal{O}(N^{2})$ time. With this, we show that measurement in the computational basis approximately saturates the quantum bound and maintains the $\\mathcal{O}(A^2 N^3)$ scaling. Furthermore, the periodic information extraction makes the protocol robust to decoherence. Our results provide a framework for the design and analysis of sequential measurement in ancilla-assisted protocols.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2605.00287",
  "author_total": 3,
  "authors": [
    {
      "name": "Koray Mentesoglu"
    },
    {
      "name": "Rahul Trivedi"
    },
    {
      "name": "Sara Mouradian"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/4jmnw0143v14h.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2605.00287",
  "fulltext_url": null,
  "id": "4jmnw0143v14h",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2605.00287",
  "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",
      "1702|Quantum Information and Cryptography"
    ]
  ],
  "openalex": "W7160185445",
  "pdf_url": "https://arxiv.org/pdf/2605.00287",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-02",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/4jmnw0143v14h.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:18:31Z",
      "native_id": "2605.00287",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2605.00287"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:quant-ph",
      "subfield": "quantum"
    }
  ],
  "title": "Sequential Measurements as a Resource in Ancilla-Assisted Quantum Metrology",
  "title_text": "Sequential Measurements as a Resource in Ancilla-Assisted Quantum Metrology",
  "type": "preprint",
  "updated_at": "2026-10-30T12:18:31Z",
  "url": "https://research.draconitic.com/paper/4jmnw0143v14h",
  "venue": "arXiv",
  "versions": []
}