{
  "annotation_id": "f8478494-6e7d-4b76-8822-d96895a0d955",
  "date_created": "2026-03-02T18:01:42.411000Z",
  "date_modified": "2026-03-02T18:01:42.411000Z",
  "file_hash": "85d678afed49d64fe9f92a0946145cab0a4e22260e6f76096e1d445b1d771a71",
  "private": false,
  "record": {
    "abstract": "The entropy H_T(rho) of a state rho with respect to a channel T and the\nHolevo capacity of the channel require the solution of difficult variational\nproblems. For a class of 1-qubit channels, which contains all the extremal\nones, the problem can be significantly simplified by associating an Hermitian\nantilinear operator theta to every channel of the considered class. The\nconcurrence of the channel can be expressed by theta and turns out to be a flat\nroof. This allows to write down an explicit expression for H_T. Its maximum\nwould give the Holevo (1-shot) capacity.",
    "arxiv_id": "quant-ph/0011106",
    "authors": [
      "Armin Uhlmann"
    ],
    "categories": [
      "quant-ph"
    ],
    "doi": "10.1088/0305-4470/34/35/329",
    "journal_ref": "J. Phys. A: Math. Gen. 34 (2001) 7047 - 7055",
    "title": "On 1-qubit channels",
    "url": "https://arxiv.org/abs/quant-ph/0011106"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "c9e531c7-6e3b-42ac-a251-c7202f3a674f",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}