{
  "annotation_id": "4f78c76a-3aff-4788-86fa-be2de217b878",
  "date_created": "2026-03-02T18:02:41.486000Z",
  "date_modified": "2026-03-02T18:02:41.486000Z",
  "file_hash": "71c001ff842933bf6639a93a06db87e30b4b7a9356f3f47d30d78b7200d21d21",
  "private": false,
  "record": {
    "abstract": "We show that optical tachyonic dispersion corresponding to superluminal\n(faster than-light) group velocities characterizes parametrically amplifying\nmedia. The turn-on of parametric amplification in finite media, followed by\nillumination by spectrally narrow probe wavepackets, can give rise to transient\ntachyonic wavepackets. In the stable (sub-threshold) operating regime of an\noptical phase conjugator it is possible to transmit probe pulses with a\nsuperluminally advanced peak, whereas conjugate reflection is always\nsubluminal. In the unstable (above-threshold) regime, superluminal response\noccurs both in reflection and in transmission, at times preceding the onset of\nexponential growth due to the instability. Remarkably, the quantum information\ntransmitted by probe or conjugate pulses, albeit causal, is confined to times\ncorresponding to superluminal velocities. These phenomena are explicitly\nanalyzed for four-wave mixing, stimulated Raman scattering and parametric\ndownconversion.",
    "arxiv_id": "quant-ph/9805040",
    "authors": [
      "G. Kurizki",
      "A. E. Kozhekin",
      "A. G. Kofman",
      "M. Blaauboer"
    ],
    "categories": [
      "quant-ph",
      "physics.optics"
    ],
    "journal_ref": "Opt.Spectrosc.87:505-512,1999",
    "title": "Optical Tachyons in Parametric Amplifiers: How Fast Can Quantum   Information Travel?",
    "url": "https://arxiv.org/abs/quant-ph/9805040"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "173f9df2-be6d-4657-a539-0a9899f902b7",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}