{
  "id": "quant-ph/0111107",
  "version": "v1",
  "published": "2001-11-20T17:23:42.000Z",
  "updated": "2001-11-20T17:23:42.000Z",
  "title": "Structural physical approximations of unphysical maps and generalized quantum measurements",
  "authors": [
    "Jaromir Fiurasek"
  ],
  "comment": "4 pages, RevTeX 4",
  "journal": "Phys. Rev. A 66, 052315 (2002).",
  "doi": "10.1103/PhysRevA.66.052315",
  "categories": [
    "quant-ph"
  ],
  "abstract": "We investigate properties of the structural physical approximation (SPA) of the partial transposition map recently introduced by Horodecki and Ekert [quant-ph/0111064]. We focus on the case of two-qubit states and show that in this case the map has the structure of a generalized quantum measurement followed by preparation of a suitable output state. We also introduce SPA for map that transforms two copies of density matrix of a single qubit onto a square of that matrix. We prove that also this map is essentially a generalized quantum measurement.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2001-11-20T17:23:42.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "generalized quantum measurement",
      "structural physical approximation",
      "unphysical maps",
      "partial transposition map",
      "density matrix"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "publisher": "APS",
      "journal": "Phys. Rev. A"
    },
    "note": {
      "typesetting": "RevTeX",
      "pages": 4,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}