{
  "annotation_id": "1658a973-5ff3-42dc-8a0a-8b90e728e9d3",
  "date_created": "2026-03-02T18:02:30.341000Z",
  "date_modified": "2026-03-02T18:02:30.341000Z",
  "file_hash": "4bca1e09ec4cc27a6efb3417bb5b7c312b438484c278e02f71cd37e5e4159dc5",
  "private": false,
  "record": {
    "abstract": "We consider a possible detector-efficiency loophole in experiments that\ndetect entanglement via the local measurement of witness operators. Here, only\nlocal properties of the detectors are known. We derive a general threshold for\nthe detector efficiencies which guarantees that a negative expectation value of\na witness is due to entanglement, rather than to erroneous detectors. This\nthreshold depends on the local decomposition of the witness and its measured\nexpectation value. For two-qubit witnesses we find the local operator\ndecomposition that is optimal with respect to closing the loophole.",
    "arxiv_id": "quant-ph/0608058",
    "authors": [
      "Patrick Skwara",
      "Hermann Kampermann",
      "Matthias Kleinmann",
      "Dagmar Bruss"
    ],
    "categories": [
      "quant-ph"
    ],
    "doi": "10.1103/PhysRevA.76.012312",
    "journal_ref": "Phys. Rev. A 76, 012312 (2007)",
    "title": "Entanglement witnesses and a loophole problem",
    "url": "https://arxiv.org/abs/quant-ph/0608058"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "498cc571-aba6-4208-93f9-040ac86e9a91",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}