{
  "annotation_id": "6bf84976-e9f3-448a-ac87-3b276092a536",
  "date_created": "2026-03-02T18:02:34.701000Z",
  "date_modified": "2026-03-02T18:02:34.701000Z",
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  "record": {
    "abstract": "We propose a scheme for encoding logical qubits in a subspace protected\nagainst collective rotations around the propagation axis using the polarization\nand transverse spatial degrees of freedom of single photons. This encoding\nallows for quantum key distribution without the need of a shared reference\nframe. We present methods to generate entangled states of two logical qubits\nusing present day down-conversion sources and linear optics, and show that the\napplication of these entangled logical states to quantum information schemes\nallows for alignment-free tests of Bell\u0027s inequalities, quantum dense coding\nand quantum teleportation.",
    "arxiv_id": "quant-ph/0703059",
    "authors": [
      "L. Aolita",
      "S. P. Walborn"
    ],
    "categories": [
      "quant-ph"
    ],
    "doi": "10.1103/PhysRevLett.98.100501",
    "journal_ref": "Phys. Rev. Lett. 98, 100501 (2007)",
    "title": "Quantum communication without alignment using multiple-qubit   single-photon states",
    "url": "https://arxiv.org/abs/quant-ph/0703059"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "9337733c-f812-4844-ab49-56153462a6a7",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}