{
  "annotation_id": "b2b9fc7a-a2a2-40db-bc7a-7b6d3137f4c9",
  "date_created": "2026-03-02T18:02:48.587000Z",
  "date_modified": "2026-03-02T18:02:48.587000Z",
  "file_hash": "84a34b6b3d2c1d2a5f0ff300e70829372556e8a408f3c2a7331d1c6473f496c9",
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  "record": {
    "abstract": "A method for preparing a loophole-free four-photon Bell experiments which\nrequires a detection efficiency of 67% is proposed. It enables realistic\ndetection efficiencies of 75% at a visibility of 85%. Two type-II crystals each\ndown convert one correlated photon pair and we entangle one photon from one\npair with one photon from the other pair on a highly transparent beam splitter.\nThe entanglement selects two other conjugate photons into a Bell state. Wide\nsolid angles for the conjugate photons then enable us to collect close to 100%\nof them. The cases when both photon pairs come from only one of the two\ncrystals are successfully taken into account. Hardy\u0027s equalities are discussed.",
    "arxiv_id": "quant-ph/9907039",
    "authors": [
      "Mladen Pavicic"
    ],
    "categories": [
      "quant-ph"
    ],
    "doi": "10.1016/S0030-4018(97)00285-X",
    "journal_ref": "Opt.Commun. 142 (1997) 308-314",
    "title": "A method for reaching detection efficiencies necessary for optical   loophole-free Bell experiments",
    "url": "https://arxiv.org/abs/quant-ph/9907039"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "e7cd99bd-42ae-4691-8984-3f58c227a37c",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}