{
  "annotation_id": "6dbd3b4e-cc1f-4619-8696-e32361a68464",
  "date_created": "2026-03-02T18:02:20.140000Z",
  "date_modified": "2026-03-02T18:02:20.140000Z",
  "file_hash": "c95990848304db6b6e3e881e3bdad3fc3054f6531f7051a11bb6711c5a17fbd2",
  "private": false,
  "record": {
    "abstract": "Given a large number N of copies of a qubit state of which we wish to\nestimate its purity, we prove that separable-measurement protocols can be as\nefficient as the optimal joint-measurement one if classical communication is\nused. This shows that the optimal estimation of the entanglement of a two-qubit\nstate can also be achieved asymptotically with fully separable measurements.\nThus, quantum memories provide no advantage in this situation. The relationship\nbetween our global Bayesian approach and the quantum Cramer-Rao bound is\ndiscussed.",
    "arxiv_id": "quant-ph/0509087",
    "authors": [
      "E. Bagan",
      "M. A. Ballester",
      "R. Munoz-Tapia",
      "O. Romero-Isart"
    ],
    "categories": [
      "quant-ph"
    ],
    "doi": "10.1103/PhysRevLett.95.110504",
    "journal_ref": "Phys. Rev. Lett 95, 110504 (2005)",
    "title": "Purity estimation with separable measurements",
    "url": "https://arxiv.org/abs/quant-ph/0509087"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "c30514a7-e865-4d73-ab67-7fe104bed9e3",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}