{
  "annotation_id": "fd339582-0871-4b3e-91d6-a47c3f165e1e",
  "date_created": "2026-03-02T18:01:48.833000Z",
  "date_modified": "2026-03-02T18:01:48.833000Z",
  "file_hash": "45fc460709c394fab39042350bb316fd15b108e02f40adc598a4a7d336124269",
  "private": false,
  "record": {
    "abstract": "For a 3-qubit Heisenberg model in a uniform magnetic field, the pairwise\nthermal entanglement of any two sites is identical due to the exchange symmetry\nof sites. In this paper we consider the effect of a non-uniform magnetic field\non the Heisenberg model, modeling a magnetic impurity on one site. Since\npairwise entanglement is calculated by tracing out one of the three sites, the\nentanglement clearly depends on which site the impurity is located. When the\nimpurity is located on the site which is traced out, that is, when it acts as\nan external field of the pair, the entanglement can be enhanced to the maximal\nvalue 1; while when the field acts on a site of the pair the corresponding\nconcurrence can only be increased from 1/3 to 2/3.",
    "arxiv_id": "quant-ph/0201025",
    "authors": [
      "Hongchen Fu",
      "Allan I Solomon",
      "Xiaoguang Wang"
    ],
    "categories": [
      "quant-ph"
    ],
    "doi": "10.1088/0305-4470/35/19/310",
    "title": "Pairwise entanglement in the XX model with a magnetic impurity",
    "url": "https://arxiv.org/abs/quant-ph/0201025"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "7541e410-1d0a-4e99-80ef-aea3fb4f6e21",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}