{
  "annotation_id": "04d2164e-caf9-4582-9b4f-98e88833378b",
  "date_created": "2026-03-02T18:02:47.724000Z",
  "date_modified": "2026-03-02T18:02:47.724000Z",
  "file_hash": "436c467a51a3e35fd756e0d340d12230add00a10efe0437630da75a76fe1b37c",
  "private": false,
  "record": {
    "abstract": "We present optimal and minimal measurements on identical copies of an unknown\nstate of a qubit when the quality of measuring strategies is quantified with\nthe gain of information (Kullback of probability distributions). We also show\nthat the maximal gain of information occurs, among isotropic priors, when the\nstate is known to be pure. Universality of optimal measurements follows from\nour results: using the fidelity or the gain of information, two different\nfigures of merits, leads to exactly the same conclusions. We finally\ninvestigate the optimal capacity of $N$ copies of an unknown state as a quantum\nchannel of information.",
    "arxiv_id": "quant-ph/9907098",
    "authors": [
      "Rolf Tarrach",
      "Guifre Vidal"
    ],
    "categories": [
      "quant-ph"
    ],
    "doi": "10.1103/PhysRevA.60.R3339",
    "journal_ref": "Phys. Rev. A 60, R3339 (1999)",
    "title": "Universality of optimal measurements",
    "url": "https://arxiv.org/abs/quant-ph/9907098"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "6a42dd1f-4ed1-4105-856b-2861ca3987b4",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}