{
  "abstract": "We experimentally demonstrate a universal, parameter-independent test for asymmetric source discrimination below the diffraction limit. The test exploits spatial-mode demultiplexing (SPADE) and single-photon detection to discriminate the presence of a faint source in the vicinity of a brighter one. We develop a complete theory of the test in the presence of arbitrary modal crosstalk and show that the crosstalk-affected test retains a favorable error exponent over diffraction-limited direct imaging, provided that the crosstalk remains below a threshold $C_{\\mathrm{max}}\\simeq 1/9$. This establishes a quantitative condition under which the subdiffraction advantage of SPADE survives realistic imperfections. We experimentally test the scheme for a range of source separations and intensity ratios, without requiring prior knowledge of these parameters. The measured false-negative error rates are in good agreement with the theoretical model and systematically outperform direct imaging. These results demonstrate that SPADE provides a robust and experimentally accessible advantage for asymmetric subdiffraction hypothesis testing in the photon-starved regime, even in the presence of realistic modal crosstalk.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": "Journal reference: Phys. Rev. Lett. 137 (2026), 183801",
  "arxiv": "2605.15929",
  "author_total": 3,
  "authors": [
    {
      "name": "Luigi Santamaria Amato"
    },
    {
      "name": "Danilo Triggiani"
    },
    {
      "name": "Cosmo Lupo"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/8t305xppw0z99.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2605.15929",
  "fulltext_url": null,
  "id": "8t305xppw0z99",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2605.15929",
  "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": null,
  "pdf_url": "https://arxiv.org/pdf/2605.15929",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-21",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/8t305xppw0z99.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:36:22Z",
      "native_id": "2605.15929",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2605.15929"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:quant-ph",
      "subfield": "quantum"
    }
  ],
  "title": "Experimental subdiffraction source discrimination enabled by spatial demultiplexing and single-photon detectors",
  "title_text": "Experimental subdiffraction source discrimination enabled by spatial demultiplexing and single-photon detectors",
  "type": "preprint",
  "updated_at": "2026-11-01T12:20:44Z",
  "url": "https://research.draconitic.com/paper/8t305xppw0z99",
  "venue": "arXiv",
  "versions": [
    {
      "doi": "10.1103/xkvt-xvqm",
      "pid": null,
      "relation": "published-as",
      "title": null,
      "venue": null
    }
  ]
}