{
  "id": "1403.2376",
  "version": "v1",
  "published": "2014-03-10T08:33:29.000Z",
  "updated": "2014-03-10T08:33:29.000Z",
  "title": "Quantum Fisher Information of W States in Decoherence Channels",
  "authors": [
    "Fatih Ozaydin"
  ],
  "comment": "3 pages, 1 (eps) figure. Comments are welcome",
  "categories": [
    "quant-ph"
  ],
  "abstract": "We study the quantum Fisher information (QFI) of W states analytically with respect to SU(2) rotations in the basic decoherence channels i.e. depolarizing (DPC), amplitude damping (ADC) and phase damping (PDC), and present the interesting behavior of QFI of W states, especially when compared to that of GHZ states [Ma et al., Phys. Rev. A, 84, 022302 (2011)]. We find that when initially pure W states are under decoherence, i) DPC: as decoherence starts and increases, QFI smoothly decays; ii) ADC: just as decoherence starts, QFI exhibits a sudden drop to the shot noise level and as decoherence increases, QFI continues to decrease to zero and then increases back to the shot noise level; iii) PDC: just as decoherence starts, a sudden death of QFI occurs and QFI remains zero for any rate of decoherence, therefore W states in phase damping channel do not provide phase sensitivity. We also find that, on the contrary to GHZ states, pure or decohered W states are not sensitive with respect to rotations in z direction and the sensitivities with respect to rotations in x and y directions are equal to each other, implying no sudden change points of QFI due to competition between directions.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2014-03-10T08:33:29.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "quantum fisher information",
      "shot noise level",
      "decoherence starts",
      "ghz states",
      "basic decoherence channels"
    ],
    "publication": {
      "doi": "10.1016/j.physleta.2014.08.035",
      "journal": "Physics Letters A",
      "year": 2014,
      "month": "Sep",
      "volume": 378,
      "number": 43,
      "pages": 3161
    },
    "note": {
      "typesetting": "TeX",
      "pages": 3,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "adsabs": "2014PhLA..378.3161O"
    }
  }
}