{
  "annotation_id": "42626182-80be-406a-93bd-c6bbc7a5d9b2",
  "date_created": "2026-03-02T18:02:13.512000Z",
  "date_modified": "2026-03-02T18:02:13.512000Z",
  "file_hash": "f787efac47e210a656f74e8fc6af700ca52a539a2a6d66f8fd867f70a8ea12ad",
  "private": false,
  "record": {
    "abstract": "The concurrence of two alternate qubits in a four-qubit Heisenberg XX chain\nis investigated when a uniform magnetic field B is included. It is found that\nthere is no thermal entanglement between alternate qubits if B is close to\nzero. Magnetic field can induce entanglement in a certain range both for the\nantiferromagnetic and ferromagnetic cases. Near zero temperature, the\nentanglement undergoes two sudden changes with increasing value of the magnetic\nfield B. This is due to the changes in the ground state. This novel property\nmay be used as quantum entanglement switch. The anisotropy in the system can\nalso induce the entanglement between two alternate qubits.",
    "arxiv_id": "quant-ph/0501029",
    "authors": [
      "M. Cao",
      "S. Zhu"
    ],
    "categories": [
      "quant-ph"
    ],
    "doi": "10.1103/PhysRevA.71.034311",
    "title": "Thermal Entanglement between Alternate Qubits of a Four-qubit Heisenberg   XX Chain in a Magnetic Field",
    "url": "https://arxiv.org/abs/quant-ph/0501029"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "780814b2-3f9c-4308-9b08-88b1f0816e3b",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}