{
  "annotation_id": "cf1fd111-3368-4b65-9bb2-d21dc495c346",
  "date_created": "2026-03-02T18:02:03.252000Z",
  "date_modified": "2026-03-02T18:02:03.252000Z",
  "file_hash": "897322a06dc3b3feb60b7af4f603c5ec1e754be49926a7f0c21a58b6bbc073a1",
  "private": false,
  "record": {
    "abstract": "Here we demonstrate how para-hydrogen can be used to prepare a two-spin\nsystem in an almost pure state which is suitable for implementing nuclear\nmagnetic resonance (NMR) quantum computation. A 12ns laser pulse is used to\ninitiate a chemical reaction involving pure para-hydrogn (the nuclear spin\nsinglet of H2). The product, formed on the microsecond timescale, contains a\nhydrogen derived two-spin system with an effective spin-state purity of 0.916.\nTo achieve a comparable result by direct cooling would require an unmanageable\n(in the liquid state) effective spin temperature of 6.4mK or an impractical\nmagnetic field of 0.45MT at room temperature. The resulting spin state has an\nentanglement of formation of 0.822 and cannot be described by local hidden\nvariable models.",
    "arxiv_id": "quant-ph/0312014",
    "authors": [
      "M. S. Anwar",
      "D. Blazina",
      "H. Carteret",
      "S. B. Duckett",
      "T. K. Halstead",
      "J. A. Jones",
      "C. M. Kozak",
      "R. J. K. Taylor"
    ],
    "categories": [
      "quant-ph"
    ],
    "doi": "10.1103/PhysRevLett.93.040501",
    "journal_ref": "Phys. Rev. Lett. 93, 040501 (2004)",
    "title": "Preparing high purity initial states for nuclear magnetic resonance   quantum computing",
    "url": "https://arxiv.org/abs/quant-ph/0312014"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "ddef9ff3-2d85-4511-97f8-61bd494cbc83",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}