{
  "annotation_id": "b6a0caa3-b4e5-4758-a76a-de01f41b2102",
  "date_created": "2026-03-02T18:02:03.519000Z",
  "date_modified": "2026-03-02T18:02:03.519000Z",
  "file_hash": "ed245c4c3b344a6cdf36637bbd5c732972405efa14ef90a2c4005158cf8136b3",
  "private": false,
  "record": {
    "abstract": "The purity of a reduced state for spins that is pure in the rest frame will\nmost likely appear to degrade because spin and momentum become mixed when\nviewed by a moving observer. We show that such a boost-induced decrease in spin\npurity observed in a moving reference frame is intrinsically related to the\nspatial localization properties of the wave package observed in the rest frame.\nFurthermore, we prove that, for any localized pure state with separable spin\nand momentum in the rest frame, its reduced density matrix for spins inevitably\nappears to be mixed whenever viewed from a moving reference frame.",
    "arxiv_id": "quant-ph/0309144",
    "authors": [
      "Hui Li",
      "Jiangfeng Du"
    ],
    "categories": [
      "quant-ph"
    ],
    "doi": "10.1103/PhysRevA.70.012111",
    "journal_ref": "Phys. Rev. A 70, 012111 (2004)",
    "title": "Spatial Localization and Relativistic Transformation of Quantum Spins",
    "url": "https://arxiv.org/abs/quant-ph/0309144"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "7efb47b3-2221-42df-8a6d-f55644320970",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}