{
  "annotation_id": "f5bec41d-ff05-4e87-9441-b42a4e079c0e",
  "date_created": "2026-03-02T18:02:44.336000Z",
  "date_modified": "2026-03-02T18:02:44.336000Z",
  "file_hash": "6c08dbb97a919a364f02561d83317c1a9c3b5fcd43f8d6caad74319b09044987",
  "private": false,
  "record": {
    "abstract": "The recently derived input-output relations for the radiation field at a\ndispersive and absorbing four-port device [T. Gruner and D.-G. Welsch, Phys.\nRev. A 54, 1661 (1996)] are used to derive the unitary transformation that\nrelates the output quantum state to the input quantum state, including\nradiation and matter and without placing frequency restrictions. It is shown\nthat for each frequency the transformation can be regarded as a well-behaved\nSU(4) group transformation that can be decomposed into a product of U(2) and\nSU(2) group transformations. Each of them may be thought of as being realized\nby a particular lossless four-port device. If for narrow-bandwidth radiation\nfar from the medium resonances the absorption matrix of the four-port device\ncan be disregarded, the well-known SU(2) group transformation for a lossless\ndevice is recognized. Explicit formulas for the transformation of Fock-states\nand coherent states are given.",
    "arxiv_id": "quant-ph/9806077",
    "authors": [
      "L. Knoell",
      "S. Scheel",
      "E. Schmidt",
      "D. -G. Welsch"
    ],
    "categories": [
      "quant-ph"
    ],
    "doi": "10.1103/PhysRevA.59.4716",
    "journal_ref": "Phys. Rev. A 59, 4716 (1999)",
    "title": "Quantum state transformation by dispersive and absorbing four-port   devices",
    "url": "https://arxiv.org/abs/quant-ph/9806077"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "6d2ccae7-8a14-4953-a7b5-b7a224dae18c",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}