{
  "id": "0912.1162",
  "version": "v1",
  "published": "2009-12-07T10:10:46.000Z",
  "updated": "2009-12-07T10:10:46.000Z",
  "title": "Adaptive Optical Phase Estimation Using Time-Symmetric Quantum Smoothing",
  "authors": [
    "T. A. Wheatley",
    "D. W. Berry",
    "H. Yonezawa",
    "D. Nakane",
    "H. Arao",
    "D. T. Pope",
    "T. C. Ralph",
    "H. M. Wiseman",
    "A. Furusawa",
    "E. H. Huntington"
  ],
  "journal": "Phys Rev Lett, 104, 093601, 2010",
  "doi": "10.1103/PhysRevLett.104.093601",
  "categories": [
    "quant-ph"
  ],
  "abstract": "Quantum parameter estimation has many applications, from gravitational wave detection to quantum key distribution. We present the first experimental demonstration of the time-symmetric technique of quantum smoothing. We consider both adaptive and non-adaptive quantum smoothing, and show that both are better than their well-known time-asymmetric counterparts (quantum filtering). For the problem of estimating a stochastically varying phase shift on a coherent beam, our theory predicts that adaptive quantum smoothing (the best scheme) gives an estimate with a mean-square error up to $2\\sqrt{2}$ times smaller than that from non-adaptive quantum filtering (the standard quantum limit). The experimentally measured improvement is $2.24 \\pm 0.14$.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2009-12-07T10:10:46.000Z"
    }
  ],
  "analyses": {
    "subjects": [
      "42.50.Dv",
      "03.65.Ta",
      "03.67.-a",
      "42.50.Xa"
    ],
    "keywords": [
      "adaptive optical phase estimation",
      "time-symmetric quantum smoothing",
      "gravitational wave detection",
      "first experimental demonstration",
      "non-adaptive quantum"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "publisher": "APS",
      "journal": "Physical Review Letters",
      "year": 2010,
      "month": "Mar",
      "volume": 104,
      "number": 9,
      "pages": "093601"
    },
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "adsabs": "2010PhRvL.104i3601W"
    }
  }
}