{
  "id": "quant-ph/0503141",
  "version": "v1",
  "published": "2005-03-16T15:46:24.000Z",
  "updated": "2005-03-16T15:46:24.000Z",
  "title": "A new local invariant for quantum gates",
  "authors": [
    "Laura Koponen",
    "Ville Bergholm",
    "Martti M. Salomaa"
  ],
  "comment": "8 pages, 2 figures",
  "journal": "Quant. Inf. Comp. 6, 58 (2006)",
  "categories": [
    "quant-ph"
  ],
  "abstract": "In this paper we study the properties of two-qubit gates. We review the most common parameterizations for the local equivalence classes of two-qubit gates and the connections between them. We then introduce a new discrete local invariant, namely the number of local degrees of freedom that a gate can bind. The value of this invariant is calculated analytically for all the local equivalence classes of two-qubit gates. We find that almost all two-qubit gates can bind the full six local degrees of freedom and are in this sense more effective than the controlled-NOT gate, which only can bind four local degrees of freedom.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2005-03-16T15:46:24.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "quantum gates",
      "two-qubit gates",
      "local degrees",
      "local equivalence classes",
      "discrete local invariant"
    ],
    "tags": [
      "journal article"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 8,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "adsabs": "2005quant.ph..3141K"
    }
  }
}