{
  "id": "quant-ph/0509007",
  "version": "v5",
  "published": "2005-09-01T13:51:04.000Z",
  "updated": "2006-04-21T04:54:08.000Z",
  "title": "Decay of Loschmidt Echo Enhanced by Quantum Criticality",
  "authors": [
    "H. T. Quan",
    "Z. Song",
    "X. F. Liu",
    "P. Zanardi",
    "C. P. Sun"
  ],
  "comment": "4 pages, 3 figures",
  "journal": "Phys. Rev. Lett. 96, 140604 (2006)",
  "doi": "10.1103/PhysRevLett.96.140604",
  "categories": [
    "quant-ph",
    "cond-mat.str-el"
  ],
  "abstract": "We study the transition of a quantum system $S $ from a pure state to a mixed one, which is induced by the quantum criticality of the surrounding system $E$ coupled to it. To characterize this transition quantitatively, we carefully examine the behavior of the Loschmidt echo (LE) of $E$ modelled as an Ising model in a transverse field, which behaves as a measuring apparatus in quantum measurement. It is found that the quantum critical behavior of $E$ strongly affects its capability of enhancing the decay of LE: near the critical value of the transverse field entailing the happening of quantum phase transition, the off-diagonal elements of the reduced density matrix describing $S$ vanish sharply.",
  "revisions": [
    {
      "version": "v5",
      "updated": "2006-04-21T04:54:08.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "quantum criticality",
      "loschmidt echo",
      "transverse field",
      "quantum phase transition",
      "pure state"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "publisher": "APS",
      "journal": "Phys. Rev. Lett."
    },
    "note": {
      "typesetting": "TeX",
      "pages": 4,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}