{
  "annotation_id": "d4c6e14a-c832-40db-86fd-4c92a3b9073f",
  "date_created": "2026-03-02T18:01:52.094000Z",
  "date_modified": "2026-03-02T18:01:52.094000Z",
  "file_hash": "d2dc89ee5b4eb2bb8736e3edf34376644fd2c594421ea2ed1fd1810f3be188ed",
  "private": false,
  "record": {
    "abstract": "It is known that in phase covariant quantum cloning the equatorial states on\nthe Bloch sphere can be cloned with a fidelity higher than the optimal bound\nestablished for universal quantum cloning. We generalize this concept to\ninclude other states on the Bloch sphere with a definite $z$ component of spin.\nIt is shown that once we know the $z$ component, we can always clone a state\nwith a fidelity higher than the universal value and that of equatorial states.\nWe also make a detailed study of the entanglement properties of the output\ncopies and show that the equatorial states are the only states which give rise\nto separable density matrix for the outputs.",
    "arxiv_id": "quant-ph/0208080",
    "authors": [
      "V. Karimipour",
      "A. T. Rezakhani"
    ],
    "categories": [
      "quant-ph"
    ],
    "doi": "10.1103/PhysRevA.66.052111",
    "journal_ref": "Phys. Rev. A 66, 052111 (2002)",
    "title": "On the Phase Covariant Quantum Cloning",
    "url": "https://arxiv.org/abs/quant-ph/0208080"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "2c0af458-63bb-4c39-a844-5ebdbf5828b5",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}