{
  "annotation_id": "8a5bc84a-322d-418d-826b-03888e78f904",
  "date_created": "2026-03-02T18:01:52.568000Z",
  "date_modified": "2026-03-02T18:01:52.568000Z",
  "file_hash": "59ec1875cfe1ffae8d0beba9a21345cd06478a47d660cc6b033be0935a8d2875",
  "private": false,
  "record": {
    "abstract": "We discuss several methods for unambiguous state discrimination of N\nsymmetric coherent states using linear optics and photodetectors. One type of\nmeasurements is shown to be optimal in the limit of small photon numbers for\nany N. For the special case of N=4 this measurement can be fruitfully used by\nthe receiving end (Bob) in an implementation of the BB84 quantum key\ndistribution protocol using faint laser pulses. In particular, if Bob detects\nonly a single photon the procedure is equivalent to the standard measurement\nthat he would have to perform in a single-photon implementation of BB84, if he\ndetects two photons Bob will unambiguously know the bit sent to him in 50% of\nthe cases without having to exchange basis information, and if three photons\nare detected, Bob will know unambiguously which quantum state was sent.",
    "arxiv_id": "quant-ph/0207138",
    "authors": [
      "S. J. van Enk"
    ],
    "categories": [
      "quant-ph"
    ],
    "doi": "10.1103/PhysRevA.66.042313",
    "journal_ref": "Phys. Rev. A 66, 042313 (2002)",
    "title": "Unambiguous State Discrimination of Coherent States with Linear Optics:   Application to Quantum Cryptography",
    "url": "https://arxiv.org/abs/quant-ph/0207138"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "dae58770-bafc-4247-b38e-6bdf5f9c76cf",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}