{
  "annotation_id": "d0b8b756-4c2c-41e4-b5ff-2f9045dc08ca",
  "date_created": "2026-03-02T18:02:37.786000Z",
  "date_modified": "2026-03-02T18:02:37.786000Z",
  "file_hash": "ca650b9e160d945317520d81fa07147dfd833733ee0e0525e6dd4e8fd3a3fce6",
  "private": false,
  "record": {
    "abstract": "We analyze to what extent it is possible to copy arbitrary states of a\ntwo-level quantum system. We show that there exists a \"universal quantum\ncopying machine\", which approximately copies quantum mechanical states in such\na way that the quality of its output does not depend on the input. We also\nexamine a machine which combines a unitary transformation with a selective\nmeasurement to produce good copies of states in a neighborhood of a particular\nstate. We discuss the problem of measurement of the output states.",
    "arxiv_id": "quant-ph/9607018",
    "authors": [
      "Vladimir Buzek",
      "Mark Hillery"
    ],
    "categories": [
      "quant-ph"
    ],
    "doi": "10.1103/PhysRevA.54.1844",
    "title": "Quantum Copying: Beyond the No-Cloning Theorem",
    "url": "https://arxiv.org/abs/quant-ph/9607018"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "a7c98afe-e3aa-4ff9-bc54-e871c27ac3e3",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}