{
  "annotation_id": "939275b4-2116-4c74-b763-58b96b176a8f",
  "date_created": "2026-03-02T18:00:32.204000Z",
  "date_modified": "2026-03-02T18:00:32.204000Z",
  "file_hash": "e10d9b1f86382ec4c6b0bb57046fabd4d4e04b24a3733f18af2a35d87647433c",
  "private": false,
  "record": {
    "abstract": "It says in the report$^1$ by Wang et al. that a negative group velocity\n$u=-c/310$ is obtained and that a pulse advancement shift 62-ns is measured.\nThe authors claim that the negative group velocity is associated with\nsuperluminal light propagation and that the pulse advancement is not at odds\nwith causality or special relativity. However, it is shown here that their\nconclusions above are not true. Furthermore, I give some suggestion concerning\na re-definition of group-velocity and a new explanation in special relativity\nof causality.",
    "arxiv_id": "physics/0009034",
    "authors": [
      "Yuan-Zhong Zhang"
    ],
    "categories": [
      "physics.gen-ph",
      "physics.class-ph"
    ],
    "title": "Has superluminal light propagation been observed?",
    "url": "https://arxiv.org/abs/physics/0009034"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "b328b819-458a-4feb-9c6f-3068f2ed94b8",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}