{
  "annotation_id": "f7cf2c3d-f09d-4db5-a5e6-e47f85714aca",
  "date_created": "2026-03-02T18:02:09.394000Z",
  "date_modified": "2026-03-02T18:02:09.394000Z",
  "file_hash": "f138baef7d07bbe17ec5c9450c4dc63c2c6f134c816f5249a3042c65e35166f1",
  "private": false,
  "record": {
    "abstract": "We consider the ground state of the XY model on an infinite chain at zero\ntemperature. Following Bennett, Bernstein, Popescu, and Schumacher we use\nentropy of a sub-system as a measure of entanglement. Vidal, Latorre, Rico and\nKitaev conjectured that von Neumann entropy of a large block of neighboring\nspins approaches a constant as the size of the block increases. We evaluated\nthis limiting entropy as a function of anisotropy and transverse magnetic\nfield. We used the methods based on integrable Fredholm operators and\nRiemann-Hilbert problem. The entropy is singular at phase transitions.",
    "arxiv_id": "quant-ph/0409027",
    "authors": [
      "A. R. Its",
      "B. -Q. Jin",
      "V. E. Korepin"
    ],
    "categories": [
      "quant-ph",
      "cond-mat.stat-mech",
      "nlin.SI"
    ],
    "doi": "10.1088/0305-4470/38/13/011",
    "journal_ref": "Journal Phys. A: Math. Gen. vol 38, pages 2975-2990, 2005",
    "title": "Entanglement in XY Spin Chain",
    "url": "https://arxiv.org/abs/quant-ph/0409027"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "d0eb2a76-cff5-4cec-9d24-edc492f7d51d",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}