{
  "annotation_id": "d9abaeb5-61c5-460e-8f5e-e8c93f6e037b",
  "date_created": "2026-03-02T18:01:45.061000Z",
  "date_modified": "2026-03-02T18:01:45.061000Z",
  "file_hash": "36a4b81d2fa1f24f518acbadfb977ebc0d25efe5adef9fa832745cf64a939c98",
  "private": false,
  "record": {
    "abstract": "Quantum particles, such as spins, can be used for communicating spatial\ndirections to observers who share no common coordinate frame. We show that if\nthe emitter\u0027s signals are the orbit of a group, then the optimal detection\nmethod may not be a covariant measurement (contrary to widespread belief). It\nmay be advantageous for the receiver to use a different group and an indirect\nestimation method: first, an ordinary measurement supplies redundant numerical\nparameters; the latter are then used for a nonlinear optimal identification of\nthe signal.",
    "arxiv_id": "quant-ph/0107114",
    "authors": [
      "Asher Peres",
      "Petra F. Scudo"
    ],
    "categories": [
      "quant-ph"
    ],
    "doi": "10.1080/09500340110118449",
    "journal_ref": "J. Modern Optics 49 (2002) 1235",
    "title": "Covariant quantum measurements may not be optimal",
    "url": "https://arxiv.org/abs/quant-ph/0107114"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "a6216182-daa5-4d6f-9b06-79f4ea6333fc",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}