{
  "annotation_id": "709a6281-5659-4712-a3ca-94d02ca2030f",
  "date_created": "2026-03-02T18:00:56.816000Z",
  "date_modified": "2026-03-02T18:00:56.816000Z",
  "file_hash": "5109c32a4282316089dc38aa1a23b20fc85644c40c153b6f2e6fafaf7ae111fe",
  "private": false,
  "record": {
    "abstract": "In order to settle the problem of the \"Post constraint\" in material media, we\nconsider the propagation of a plane electromagnetic wave in a medium with a\npiecewise constant axion field. Although a constant axion field does not affect\nthe wave propagation in a homogeneous medium, we show that the reflection and\ntransmission of a wave at an interface between the two media is sensitive to\nthe difference of the axion values. This observation can be used to determine\nexperimentally the axion piece in matter despite the fact that a constant axion\nvalue does not contribute to the Maxwell equations.",
    "arxiv_id": "physics/0504172",
    "authors": [
      "Yuri N. Obukhov",
      "Friedrich W. Hehl"
    ],
    "categories": [
      "physics.optics",
      "cond-mat.mtrl-sci",
      "hep-th",
      "physics.class-ph"
    ],
    "doi": "10.1016/j.physleta.2005.05.006",
    "journal_ref": "Phys.Lett. A341 (2005) 357-365",
    "title": "Measuring a piecewise constant axion field in classical electrodynamics",
    "url": "https://arxiv.org/abs/physics/0504172"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "41fc2388-7d11-4cc4-9d94-56e4a0122eca",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}