{
  "id": "2108.00836",
  "version": "v1",
  "published": "2021-08-02T12:46:49.000Z",
  "updated": "2021-08-02T12:46:49.000Z",
  "title": "Implementation of the SMART protocol for global qubit control in silicon",
  "authors": [
    "Ingvild Hansen",
    "Amanda E. Seedhouse",
    "Kok Wai Chan",
    "Fay Hudson",
    "Kohei M. Itoh",
    "Arne Laucht",
    "Andre Saraiva",
    "Chih Hwan Yang",
    "Andrew S. Dzurak"
  ],
  "categories": [
    "cond-mat.mes-hall",
    "quant-ph"
  ],
  "abstract": "Quantum computing based on spins in the solid state allows for densely-packed arrays of quantum bits. While high-fidelity operation of single qubits has been demonstrated with individual control pulses, the operation of large-scale quantum processors requires a shift in paradigm towards global control solutions. Here we report the experimental implementation of a new type of qubit protocol -- the SMART (Sinusoidally Modulated, Always Rotating and Tailored) protocol. As with a dressed qubit, we resonantly drive a two-level system with a continuous microwave field, but here we add a tailored modulation to the dressing field to achieve increased robustness to detuning noise and microwave amplitude fluctuations. We implement this new protocol to control a single spin confined in a SiMOS quantum dot and confirm the optimal modulation conditions predicted from theory. Universal control of a single qubit is demonstrated using modulated Stark shift control via the local gate electrodes. We measure an extended coherence time of $2$ ms and an average Clifford gate fidelity $>99$ % despite the relatively long qubit gate times ($>10$ $\\unicode[serif]{x03BC}$s), constituting a significant improvement over a conventional spin qubit and a dressed qubit. This work shows that future scalable spin qubit arrays could be operated using global microwave control and local gate addressability, while maintaining robustness to relevant experimental inhomogeneities.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2021-08-02T12:46:49.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "global qubit control",
      "smart protocol",
      "implementation",
      "spin qubit",
      "relatively long qubit gate times"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}