{
  "annotation_id": "95c1e4b4-31ce-4bed-9c3a-4cc641c903c0",
  "date_created": "2026-03-02T18:01:39.321000Z",
  "date_modified": "2026-03-02T18:01:39.321000Z",
  "file_hash": "dd76736f84712352b9143cf8cf2003b33dac262f34b995683b3eb1a9acbd9468",
  "private": false,
  "record": {
    "abstract": "Applying the recently developed formalism of quantum-state transformation at\nabsorbing dielectric four-port devices [L.~Kn\\\"oll, S.~Scheel, E.~Schmidt,\nD.-G.~Welsch, and A.V.~Chizhov, Phys. Rev. A {\\bf 59}, 4716 (1999)], we\ncalculate the quantum state of the outgoing modes of a two-mode squeezed vacuum\ntransmitted through optical fibers of given extinction coefficients. Using the\nPeres--Horodecki separability criterion for continuous variable systems\n[R.~Simon, Phys. Rev. Lett. {\\bf 84}, 2726 (2000)], we compute the maximal\nlength of transmission of a two-mode squeezed vacuum through an absorbing\nsystem for which the transmitted state is still inseparable. Further, we\ncalculate the maximal gain for which inseparability can be observed in an\namplifying setup. Finally, we estimate an upper bound of the entanglement\npreserved after transmission through an absorbing system. The results show that\nthe characteristic length of entanglement degradation drastically decreases\nwith increasing strength of squeezing.",
    "arxiv_id": "quant-ph/0006026",
    "authors": [
      "Stefan Scheel",
      "Tomas Opatrny",
      "Dirk-Gunnar Welsch"
    ],
    "categories": [
      "quant-ph"
    ],
    "doi": "10.1134/1.1405221",
    "title": "Entanglement degradation of a two-mode squeezed vacuum in absorbing and   amplifying optical fibers",
    "url": "https://arxiv.org/abs/quant-ph/0006026"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "927624b7-30e0-42e4-8424-1293b3dfed98",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}