{
  "annotation_id": "f088e01b-1be2-4faa-bbde-48593e9a2c10",
  "date_created": "2026-03-02T18:02:48.008000Z",
  "date_modified": "2026-03-02T18:02:48.008000Z",
  "file_hash": "31d80b8cf438ce3e60b79efd32de1e755bb1dca6586b45a64a6a84ee5fc35268",
  "private": false,
  "record": {
    "abstract": "To reconstruct a mixed or pure quantum state of a spin s is possible through\ncoherent states: its density matrix is fixed by the probabilities to measure\nthe value s along 4s(s+1) appropriately chosen directions in space. Thus, after\ninverting the experimental data, the statistical operator is parametrized\nentirely by expectation values. On this basis, a symbolic calculus for quantum\nspins is developed, the `expectation-value representation.\u0027 It resembles the\nMoyal representation for SU(2) but two important differences exist. On the one\nhand, the symbols take values on a discrete set of points in phase space only.\nOn the other hand, no quasi-probabilities - that is, phase-space distributions\nwith negative values - are encountered in this approach.",
    "arxiv_id": "quant-ph/9904095",
    "authors": [
      "Stefan Weigert"
    ],
    "categories": [
      "quant-ph"
    ],
    "title": "A Discrete Phase-Space Calculus for Quantum Spins based on a   Reconstruction Method using Coherent States",
    "url": "https://arxiv.org/abs/quant-ph/9904095"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "0ec118a9-0b3e-4564-a6b1-6564815ce784",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}