{
  "annotation_id": "c41ff2e7-6e7c-4b2f-98ad-53cc91cf37b8",
  "date_created": "2026-03-02T18:02:24.082000Z",
  "date_modified": "2026-03-02T18:02:24.082000Z",
  "file_hash": "af82652ab5a3dd82470448a12ef90b6573dda1ac20a22a752222f411144d3dec",
  "private": false,
  "record": {
    "abstract": "We report on the experimental observation of quantum-network-compatible light\ndescribed by a non-positive Wigner function. The state is generated by photon\nsubtraction from a squeezed vacuum state produced by a continuous wave optical\nparametric amplifier. Ideally, the state is a coherent superposition of odd\nphoton number states, closely resembling a superposition of weak coherent\nstates (a Schroedinger cat), with the leading contribution from a single photon\nstate in the low parametric gain limit. Light is generated in a nearly perfect\nspatial mode with a Fourier-limited frequency bandwidth which matches well\natomic quantum memory requirements. The source is also characterized by high\nspectral brightness with about 10,000 and more events per second routinely\ngenerated. The generated state of light is the ultimate input state for testing\nquantum memories, quantum repeaters and linear optics quantum computers.",
    "arxiv_id": "quant-ph/0602198",
    "authors": [
      "J. S. Neergaard-Nielsen",
      "B. Melholt Nielsen",
      "C. Hettich",
      "K. Moelmer",
      "E. S. Polzik"
    ],
    "categories": [
      "quant-ph"
    ],
    "doi": "10.1103/PhysRevLett.97.083604",
    "journal_ref": "Phys. Rev. Lett. 97, 083604 (2006)",
    "title": "Generation of a superposition of odd photon number states for quantum   information networks",
    "url": "https://arxiv.org/abs/quant-ph/0602198"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "d3116c60-e394-40c8-8297-254b55d6b527",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}