{
  "annotation_id": "7badfff6-7fd5-4246-bab1-27d943ad0d5f",
  "date_created": "2026-03-02T18:02:38.096000Z",
  "date_modified": "2026-03-02T18:02:38.096000Z",
  "file_hash": "da6387959e1a053d331dbe7f137202d948ad4a3e2ed101e7929d873fcc7b7112",
  "private": false,
  "record": {
    "abstract": "As is well known, quantum mechanical behavior cannot, in general, be\nsimulated by a local hidden variables model. Most -if not all- the proofs of\nthis incompatibility refer to the correlations which arise when each of two (or\nmore) systems separated in space is subjected to a single ideal measurement.\nThis setting is good enough to show contradictions between local hidden\nvariables models and quantum mechanics in the case of pure states. However, as\nshown here, it is not powerful enough in the case of mixtures. This is\nillustrated by an example. In this example, the correlations which arise when\neach of two systems separated in space is subjected to a single ideal\nmeasurement are classical; only when each system is subjected to a {\\it\nsequence} of ideal measurements non-classical correlations are obtained. We\nalso ask whether there are situations for which even this last procedure is not\npowerful enough and non-ideal measurements have to be considered as well.",
    "arxiv_id": "quant-ph/9502005",
    "authors": [
      "Sandu Popescu"
    ],
    "categories": [
      "quant-ph"
    ],
    "doi": "10.1103/PhysRevLett.74.2619",
    "journal_ref": "Phys.Rev.Lett.74:2619-2622,1995",
    "title": "Bell\u0027s inequalities and density matrices. Revealing hidden nonlocality.",
    "url": "https://arxiv.org/abs/quant-ph/9502005"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "a8649f29-10c5-47b7-9c6a-d8bb4a10ea68",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}