{
  "id": "quant-ph/0606139",
  "version": "v4",
  "published": "2006-06-16T13:06:33.000Z",
  "updated": "2007-03-08T07:59:01.000Z",
  "title": "A Finite de Finetti Theorem for Infinite-Dimensional Systems",
  "authors": [
    "Christian D'Cruz",
    "Tobias J. Osborne",
    "Ruediger Schack"
  ],
  "comment": "4 pages, 2 figures",
  "journal": "Phys. Rev. Lett. 98, 160406 (2007)",
  "doi": "10.1103/PhysRevLett.98.160406",
  "categories": [
    "quant-ph"
  ],
  "abstract": "We formulate and prove a de Finetti representation theorem for finitely exchangeable states of a quantum system consisting of k infinite-dimensional subsystems. The theorem is valid for states that can be written as the partial trace of a pure state chosen from a family of subsets C_n of the full symmetric subspace for $n$ subsystems. We show that such states become arbitrarily close to mixtures of pure power states as n increases. We give a second equivalent characterization of the family C_n.",
  "revisions": [
    {
      "version": "v4",
      "updated": "2007-03-08T07:59:01.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "infinite-dimensional systems",
      "finetti theorem",
      "pure power states",
      "full symmetric subspace",
      "finetti representation theorem"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "publisher": "APS",
      "journal": "Phys. Rev. Lett."
    },
    "note": {
      "typesetting": "TeX",
      "pages": 4,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}