{
  "abstract": "We consider unstructured search using multimode bosonic quantum systems under energy constraints. The task is to locate an unknown marked mode among $N$ possibilities using arbitrary control, subject to a time-averaged mean-boson-number budget $n_{\\text{b}}\\gg 1$. We analyze a continuous-time phase-shift oracle of strength $B_{0}$, with cost given by the total oracle time, and a discrete oracle with fixed phase $ϕ_{0}$, with cost given by the number of queries. We give algorithms that identify the target with query complexity $O(\\sqrt{N}/{n_{\\text{b}}}B_{0})$ for continuous-time oracles or $O(\\sqrt{N}/n_{\\text{b}} |{\\sin(ϕ_{0}/{2})}|)$ for discrete oracles with $n_{\\text{b}} |{\\sin(ϕ_{0}/{2})}|=O(1)$. In contrast, for discrete oracles with $n_{\\text{b}} |{\\sin(ϕ_{0}/{2})}|=Ω(1)$, we provide an algorithm using $O(\\max\\{1,\\sqrt{N/n_{\\text{b}}|{\\sin(ϕ_{0}/{2})}|}\\})$ queries. We also prove matching lower bounds on the query complexity, showing that these algorithms are asymptotically optimal. Furthermore, we show that, in the absence of loss, non-Gaussianity is necessary to achieve the optimal joint query scaling in $N$ and $n_{\\text{b}}$, but entanglement is not. Under uniform boson loss at rate $γ$, we prove a query lower bound of $Ω( γN / n _{\\text{b}} B_{0}^{2} )$, attained for $γ= Ω(B_{0} \\sqrt{n _{\\text{b}}/N})$ using coherent-state probes. Finally, we propose experimental implementations using multipass optical microscopy or superconducting circuits as potential routes to speeding up imaging or device calibration with a low boson-number budget.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.17163",
  "author_total": 7,
  "authors": [
    {
      "name": "Yu-Xin Wang"
    },
    {
      "name": "Erfan Abbasgholinejad"
    },
    {
      "name": "Supratik Sarkar"
    },
    {
      "name": "Sharoon Austin"
    },
    {
      "name": "Andrew M. Childs"
    },
    {
      "name": "Alexey V. Gorshkov"
    },
    {
      "name": "Mohammad Hafezi"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/dbcc9y97keh45.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.17163",
  "fulltext_url": null,
  "id": "dbcc9y97keh45",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.17163",
  "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",
      "1702|Quantum Computing Algorithms and Architecture"
    ]
  ],
  "openalex": "W7221760526",
  "pdf_url": "https://arxiv.org/pdf/2610.17163",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-12",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/dbcc9y97keh45.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:29:06Z",
      "native_id": "2610.17163",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.17163"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:quant-ph",
      "subfield": "quantum"
    }
  ],
  "title": "Bosonic unstructured search: quantum enhancement without entanglement",
  "title_text": "Bosonic unstructured search: quantum enhancement without entanglement",
  "type": "preprint",
  "updated_at": "2026-10-30T12:29:06Z",
  "url": "https://research.draconitic.com/paper/dbcc9y97keh45",
  "venue": "arXiv",
  "versions": []
}