{
  "annotation_id": "7a4fc2d6-c382-40eb-8029-531d2d8c8304",
  "date_created": "2026-03-02T18:00:53.101000Z",
  "date_modified": "2026-03-02T18:00:53.101000Z",
  "file_hash": "1bbbf6710499817e29108621729e983ca4b06e4d8363841f37b63f448cd614fa",
  "private": false,
  "record": {
    "abstract": "The sign of the refractive index of any medium is soley determined by the\nrequirement that the propagation of an electromagnetic wave obeys Einstein\ncausality. Our analysis shows that this requirement predicts that the real part\nof the refractive index may be negative in an isotropic medium even if the\nelectric permittivity and the magnetic permeability are both positive. Such a\nsystem may be a route to negative index media at optical frequencies. We also\ndemonstrate that the refractive index may be positive in left-handed media that\ncontain two molecular species where one is in its excited state.",
    "arxiv_id": "physics/0408103",
    "authors": [
      "Yi-Fan Chen",
      "Peer Fischer",
      "Frank W. Wise"
    ],
    "categories": [
      "physics.optics"
    ],
    "doi": "10.1103/PhysRevLett.95.067402",
    "journal_ref": "Phys. Rev. Lett. 95, 067402 (2005)",
    "title": "A right-handed isotropic medium with a negative refractive index",
    "url": "https://arxiv.org/abs/physics/0408103"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "438fe98d-246d-4f47-9258-9a6e2096214a",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}