{
  "annotation_id": "b7f8d712-8c50-44c4-9ad2-fcb7263dffec",
  "date_created": "2026-03-02T18:01:48.888000Z",
  "date_modified": "2026-03-02T18:01:48.888000Z",
  "file_hash": "a5241a343d56e22a0b8a6878a86bc71b04df4eb8e1caee81d7bdf9962ac69154",
  "private": false,
  "record": {
    "abstract": "What entanglement is present in naturally occurring physical systems at\nthermal equilibrium? Most such systems are intractable and it is desirable to\nstudy simple but realistic systems which can be solved. An example of such a\nsystem is the 1D infinite-lattice anisotropic XY model. This model is exactly\nsolvable using the Jordan-Wigner transform, and it is possible to calculate the\ntwo-site reduced density matrix for all pairs of sites. Using the two-site\ndensity matrix, the entanglement of formation between any two sites is\ncalculated for all parameter values and temperatures. We also study the\nentanglement in the transverse Ising model, a special case of the XY model,\nwhich exhibits a quantum phase transition. It is found that the next-nearest\nneighbour entanglement (though not the nearest-neighbour entanglement) is a\nmaximum at the critical point. Furthermore, we show that the critical point in\nthe transverse Ising model corresponds to a transition in the behaviour of the\nentanglement between a single site and the remainder of the lattice.",
    "arxiv_id": "quant-ph/0202162",
    "authors": [
      "Tobias J. Osborne",
      "Michael A. Nielsen"
    ],
    "categories": [
      "quant-ph",
      "cond-mat"
    ],
    "doi": "10.1103/PhysRevA.66.032110",
    "journal_ref": "Phys. Rev. A 66, 032110 (2002)",
    "title": "Entanglement in a simple quantum phase transition",
    "url": "https://arxiv.org/abs/quant-ph/0202162"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "47244d4f-d2db-44b2-83a9-2e95d07ff814",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}