{
  "annotation_id": "483713f8-156d-4b97-81ac-3918fdad43f9",
  "date_created": "2026-03-02T18:02:03.113000Z",
  "date_modified": "2026-03-02T18:02:03.113000Z",
  "file_hash": "7cff9c85c46fee88e26925a1de6614438a420eeeeb2b241988adc217b03d3d25",
  "private": false,
  "record": {
    "abstract": "Decoherence-free states protect quantum information from collective noise,\nthe predominant cause of decoherence in current implementations of quantum\ncommunication and computation. Here we demonstrate that spontaneous parametric\ndown-conversion can be used to generate four-photon states which enable the\nencoding of one qubit in a decoherence-free subspace. The immunity against\nnoise is verified by quantum state tomography of the encoded qubit. We show\nthat particular states of the encoded qubit can be distinguished by local\nmeasurements on the four photons only.",
    "arxiv_id": "quant-ph/0309041",
    "authors": [
      "Mohamed Bourennane",
      "Manfred Eibl",
      "Sascha Gaertner",
      "Christian Kurtsiefer",
      "Adan Cabello",
      "Harald Weinfurter"
    ],
    "categories": [
      "quant-ph"
    ],
    "doi": "10.1103/PhysRevLett.92.107901",
    "journal_ref": "Phys. Rev. Lett. 92 107901 (2004)",
    "title": "Decoherence-Free Quantum Information Processing with Four-Photon   Entangled States",
    "url": "https://arxiv.org/abs/quant-ph/0309041"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "65de28e0-97b6-4398-8a1a-96bf95cd2a41",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}