{
  "annotation_id": "413f3633-c1b7-453a-bddc-24a4885dfe58",
  "date_created": "2026-03-02T18:02:37.513000Z",
  "date_modified": "2026-03-02T18:02:37.513000Z",
  "file_hash": "680426955029f33a0fcee1dbe663254b13517274360d0888a6e3e44d3dd5b1ce",
  "private": false,
  "record": {
    "abstract": "How well one can copy an arbitrary qubit? To answer this question we consider\ntwo arbitrary vectors in a two-dimensional state space and an abstract copying\ntransformation which will copy these two vectors. If the vectors are\northogonal, then perfect copies can be made. If they are not, then errors will\nbe introduced. The size of the error depends on the inner product of the two\noriginal vectors. We derive a lower bound for the amount of noise induced by\nquantum copying. We examine both copying transformations which produce one copy\nand transformations which produce many, and show that the quality of each copy\ndecreases as the number of copies increases.",
    "arxiv_id": "quant-ph/9701034",
    "authors": [
      "Mark Hillery",
      "Vladimir Buzek"
    ],
    "categories": [
      "quant-ph"
    ],
    "doi": "10.1103/PhysRevA.56.1212",
    "title": "Quantum copying: Fundamental inequalities",
    "url": "https://arxiv.org/abs/quant-ph/9701034"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "9d2d1fe2-739d-42ed-b30c-4bf36d927587",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}