{
  "annotation_id": "f128aa57-b427-4861-9db2-a24a37eab858",
  "date_created": "2026-03-02T18:02:13.564000Z",
  "date_modified": "2026-03-02T18:02:13.564000Z",
  "file_hash": "de7b52f36ef2598bba0ef61f8ab66d222291cea39e20798ceb28107d61a45906",
  "private": false,
  "record": {
    "abstract": "We consider travelling-wave parametric down-conversion in the high-gain\nregime and present the experimental demonstration of the quantum character of\nthe spatial fluctuations in the system. In addition to showing the presence of\nsub-shot noise fluctuations in the intensity difference, we demonstrate that\nthe peak value of the normalized spatial correlations between signal and idler\nlies well above the line marking the boundary between the classical and the\nquantum domain. This effect is equivalent to the apparent violation of the\nCauchy-Schwartz inequality, predicted by some of us years ago, which represents\na spatial analogue of photon antibunching in time. Finally, we analyse\nnumerically the transition from the quantum to the classical regime when the\ngain is increased and we emphasize the role of the inaccuracy in the\ndetermination of the symmetry center of the signal/idler pattern in the\nfar-field plane.",
    "arxiv_id": "quant-ph/0502047",
    "authors": [
      "O. Jedrkiewicz",
      "E. Brambilla",
      "M. Bache",
      "A. Gatti",
      "L. A. Lugiato",
      "P. Di Trapani"
    ],
    "categories": [
      "quant-ph"
    ],
    "doi": "10.1080/09500340500217670",
    "journal_ref": "Journal of Modern Optics 53, 575-595 (2006)",
    "title": "Quantum spatial correlations in high-gain parametric down-conversion   measured by means of a CCD camera",
    "url": "https://arxiv.org/abs/quant-ph/0502047"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "d64916f4-e1b2-46ea-826b-036634bb22e3",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}