{
  "annotation_id": "670c07ef-958a-4eb8-a85c-71586e7fe24e",
  "date_created": "2026-03-02T18:02:13.225000Z",
  "date_modified": "2026-03-02T18:02:13.225000Z",
  "file_hash": "3974313b5b4f1f224826c158852ac1d3af3b9466afb6850f2601206f80cf8830",
  "private": false,
  "record": {
    "abstract": "We investigate the unambiguous comparison of quantum states in a scenario\nthat is more general than the one that was originally suggested by Barnett et\nal. First, we find the optimal solution for the comparison of two states taken\nfrom a set of two pure states with arbitrary a priori probabilities. We show\nthat the optimal coherent measurement is always superior to the optimal\nincoherent measurement. Second, we develop a strategy for the comparison of two\nstates from a set of N pure states, and find an optimal solution for some\nparameter range when N=3. In both cases we use the reduction method for the\ncorresponding problem of mixed state discrimination, as introduced by Raynal et\nal., which reduces the problem to the discrimination of two pure states only\nfor N=2. Finally, we provide a necessary and sufficient condition for\nunambiguous comparison of mixed states to be possible.",
    "arxiv_id": "quant-ph/0503012",
    "authors": [
      "M. Kleinmann",
      "H. Kampermann",
      "D. Bruss"
    ],
    "categories": [
      "quant-ph"
    ],
    "doi": "10.1103/PhysRevA.72.032308",
    "journal_ref": "Phys. Rev. A 72, 032308 (2005)",
    "title": "On the generalization of quantum state comparison",
    "url": "https://arxiv.org/abs/quant-ph/0503012"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "b45f076e-aed8-4b37-855e-70cf39e215bc",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}