{
  "id": "1410.0663",
  "version": "v1",
  "published": "2014-10-02T19:40:29.000Z",
  "updated": "2014-10-02T19:40:29.000Z",
  "title": "Phase-noise limitations on single-photon cross-phase modulation with differing group velocities",
  "authors": [
    "Justin Dove",
    "Christopher Chudzicki",
    "Jeffrey H. Shapiro"
  ],
  "comment": "8 pages, 4 figures",
  "categories": [
    "quant-ph"
  ],
  "abstract": "A framework is established for evaluating {\\sc cphase} gates that use single-photon cross-phase modulation (XPM) originating from the Kerr nonlinearity. Prior work Phys.~Rev.~A {\\bf 73,} 062305 (2006)], which assumed that the control and target pulses propagated at the same group velocity, showed that the causality-induced phase noise required by a non-instantaneous XPM response function precluded the possibility of high-fidelity $\\pi$-radian conditional phase shifts. The framework presented herein incorporates the more realistic case of group-velocity disparity between the control and target pulses, as employed in existing XPM-based fiber-optical switches. Nevertheless, the causality-induced phase noise identified in [Phys.~Rev.~A {\\bf 73,} 062305 (2006)] still rules out high-fidelity $\\pi$-radian conditional phase shifts. This is shown to be so for both a reasonable theoretical model for the XPM response function and for the experimentally-measured XPM response function of silica-core fiber.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2014-10-02T19:40:29.000Z"
    }
  ],
  "analyses": {
    "subjects": [
      "03.67.Lx",
      "42.50.Ex",
      "42.65.Hw"
    ],
    "keywords": [
      "group velocity",
      "single-photon cross-phase modulation",
      "differing group velocities",
      "radian conditional phase shifts",
      "phase-noise limitations"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "doi": "10.1103/PhysRevA.90.062314",
      "journal": "Physical Review A",
      "year": 2014,
      "month": "Dec",
      "volume": 90,
      "number": 6,
      "pages": "062314"
    },
    "note": {
      "typesetting": "TeX",
      "pages": 8,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "adsabs": "2014PhRvA..90f2314D"
    }
  }
}