{
  "annotation_id": "b7659876-4b0e-44f3-8e70-4fe6e9a241ab",
  "date_created": "2026-03-02T18:01:56.070000Z",
  "date_modified": "2026-03-02T18:01:56.070000Z",
  "file_hash": "4622886ed836067bc0092e7cd8fdabd51500d49c9c615ff3598b55909f85c9d7",
  "private": false,
  "record": {
    "abstract": "We present a procedure inspired by dense coding, which enables a highly\nefficient transmission of information of a continuous nature. The procedure\nrequires the sender and the recipient to share a maximally entangled state. We\ndeal with the concrete problem of aligning reference frames or trihedra by\nmeans of a quantum system. We find the optimal covariant measurement and\ncompute the corresponding average error, which has a remarkably simple close\nform. The connection of this procedure with that of estimating unitary\ntransformations on qubits is briefly discussed.",
    "arxiv_id": "quant-ph/0303019",
    "authors": [
      "E. Bagan",
      "M. Baig",
      "R. Munoz-Tapia"
    ],
    "categories": [
      "quant-ph"
    ],
    "doi": "10.1103/PhysRevA.69.050303",
    "journal_ref": "Phys. Rev. A 69, 050303 (2004)",
    "title": "Entanglement assisted alignment of reference frames using a dense   covariant coding",
    "url": "https://arxiv.org/abs/quant-ph/0303019"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "ef8511da-a454-4c8b-a445-313f1e335356",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}