{
  "annotation_id": "dc1bb646-b06d-43ae-b7b2-40fdf4372be3",
  "date_created": "2026-03-02T18:01:35.857000Z",
  "date_modified": "2026-03-02T18:01:35.857000Z",
  "file_hash": "4770c0ca9d93c4409af3cefb69a15ff9225e548d7b23152e4c0b1e2e9130b01d",
  "private": false,
  "record": {
    "abstract": "Some new identities for quantum variance and covariance involving commutators\nare presented, in which the density matrix and the operators are treated\nsymmetrically. A measure of entanglement is proposed for bipartite systems,\nbased on covariance. This works for two- and three-component systems but\nproduces ambiguities for multicomponent systems of composite dimension. Its\nrelationship to angular momentum dispersion for symmetric symmetric spin states\nis described.",
    "arxiv_id": "quant-ph/0001076",
    "authors": [
      "R I A Davis",
      "R Delbourgo",
      "P D Jarvis"
    ],
    "categories": [
      "quant-ph"
    ],
    "doi": "10.1088/0305-4470/33/9/312",
    "title": "Covariance, correlation and entanglement",
    "url": "https://arxiv.org/abs/quant-ph/0001076"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "04d08e00-ede1-4256-9323-8db44bed11a0",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}