{
  "annotation_id": "7b2d9faa-016b-4bfd-9f11-a29eae6d1112",
  "date_created": "2026-03-02T18:01:59.127000Z",
  "date_modified": "2026-03-02T18:01:59.127000Z",
  "file_hash": "f20c75a252c9daa867f8db7bacbaed2b55958b038bdfd0f0125b7aa76d843b0c",
  "private": false,
  "record": {
    "abstract": "We demonstrate that a necessary precondition for unconditionally secure\nquantum key distribution is that sender and receiver can use the available\nmeasurement results to prove the presence of entanglement in a quantum state\nthat is effectively distributed between them. One can thus systematically\nsearch for entanglement using the class of entanglement witness operators that\ncan be constructed from the observed data. We apply such analysis to two\nwell-known quantum key distribution protocols, namely the 4-state protocol and\nthe 6-state protocol. As a special case, we show that, for some asymmetric\nerror patterns, the presence of entanglement can be proven even for error rates\nabove 25% (4-state protocol) and 33% (6-state protocol).",
    "arxiv_id": "quant-ph/0307151",
    "authors": [
      "Marcos Curty",
      "Maciej Lewenstein",
      "Norbert L\u00fctkenhaus"
    ],
    "categories": [
      "quant-ph"
    ],
    "doi": "10.1103/PhysRevLett.92.217903",
    "journal_ref": "Phys. Rev. Lett. 92, 217903 (2004)",
    "title": "Entanglement as precondition for secure quantum key distribution",
    "url": "https://arxiv.org/abs/quant-ph/0307151"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "9e1eb6a7-23c0-480a-9662-2342e94befe4",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}