{
  "annotation_id": "21773b45-147a-43ab-b867-9727ba2dce9c",
  "date_created": "2026-03-02T18:02:27.615000Z",
  "date_modified": "2026-03-02T18:02:27.615000Z",
  "file_hash": "0308b9e6348899a60a862ac90f0cd4615862e08874882249fc542b7e8b8682fa",
  "private": false,
  "record": {
    "abstract": "In this paper we study the concurrence and the block-block entanglement in\nthe $S=1/2$ spin ladder with four-spin ring exchange by the exact\ndiagonalization method of finite cluster of spins. The relationship between the\nglobal phase diagram and the ground-state entanglement is investigated. It is\nshown that the block-block entanglement of different block size and geometry\nmanifests richer information of the system. We find that the extremal point of\nthe two-site block-block entanglement on the rung locates a transition point\nexactly due to SU(4) symmetry at this point. The scaling behavior of the\nblock-block entanglement is discussed. Our results suggest that the block-block\nentanglement can be used as a convenient marker of quantum phase transition in\nsome complex spin systems.",
    "arxiv_id": "quant-ph/0606207",
    "authors": [
      "Jun-Liang Song",
      "Shi-Jian Gu",
      "Hai-Qing Lin"
    ],
    "categories": [
      "quant-ph"
    ],
    "doi": "10.1103/PhysRevB.74.155119",
    "journal_ref": "Phys. Rev. B 74, 155119 (2006).",
    "title": "Quantum Entanglement in the S=1/2 Spin Ladder with Ring Exchange",
    "url": "https://arxiv.org/abs/quant-ph/0606207"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "6d9f277b-d594-4179-b0c8-fb1c7350db96",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}