{
  "id": "1005.3436",
  "version": "v1",
  "published": "2010-05-19T13:30:11.000Z",
  "updated": "2010-05-19T13:30:11.000Z",
  "title": "Single-shot qubit readout in circuit Quantum Electrodynamics",
  "authors": [
    "François Mallet",
    "Florian R. Ong",
    "Agustin Palacios-Laloy",
    "François Nguyen",
    "Patrice Bertet",
    "Denis Vion",
    "Daniel Esteve"
  ],
  "comment": "14 pages including 4 figures, preprint format",
  "journal": "Nature Physics 5, 791-795 (27 September 2009)",
  "doi": "10.1038/nphys1400",
  "categories": [
    "quant-ph",
    "cond-mat.supr-con"
  ],
  "abstract": "The future development of quantum information using superconducting circuits requires Josephson qubits [1] with long coherence times combined to a high-fidelity readout. Major progress in the control of coherence has recently been achieved using circuit quantum electrodynamics (cQED) architectures [2, 3], where the qubit is embedded in a coplanar waveguide resonator (CPWR) which both provides a well controlled electromagnetic environment and serves as qubit readout. In particular a new qubit design, the transmon, yields reproducibly long coherence times [4, 5]. However, a high-fidelity single-shot readout of the transmon, highly desirable for running simple quantum algorithms or measur- ing quantum correlations in multi-qubit experiments, is still lacking. In this work, we demonstrate a new transmon circuit where the CPWR is turned into a sample-and-hold detector, namely a Josephson Bifurcation Amplifer (JBA) [6, 7], which allows both fast measurement and single-shot discrimination of the qubit states. We report Rabi oscillations with a high visibility of 94% together with dephasing and relaxation times longer than 0:5 \\mu\\s. By performing two subsequent measurements, we also demonstrate that this new readout does not induce extra qubit relaxation.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2010-05-19T13:30:11.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "circuit quantum electrodynamics",
      "single-shot qubit readout",
      "yields reproducibly long coherence times",
      "induce extra qubit relaxation",
      "coplanar waveguide resonator"
    ],
    "tags": [
      "journal article"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 14,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "adsabs": "2010arXiv1005.3436M"
    }
  }
}