{
  "id": "2203.09003",
  "version": "v1",
  "published": "2022-03-17T00:48:30.000Z",
  "updated": "2022-03-17T00:48:30.000Z",
  "title": "Self-Testing of a Single Quantum System: Theory and Experiment",
  "authors": [
    "Xiao-Min Hu",
    "Yi Xie",
    "Atul Singh Arora",
    "Ming-Zhong Ai",
    "Kishor Bharti",
    "Jie Zhang",
    "Wei Wu",
    "Ping-Xing Chen",
    "Jin-Ming Cui",
    "Bi-Heng Liu",
    "Yun-Feng Huang",
    "Chuan-Feng Li",
    "Guang-Can Guo",
    "Jérémie Roland",
    "Adán Cabello",
    "Leong-Chuan Kwek"
  ],
  "comment": "19+6 pages, 2+1 figures",
  "categories": [
    "quant-ph",
    "physics.atom-ph"
  ],
  "abstract": "Certifying individual quantum devices with minimal assumptions is crucial for the development of quantum technologies. Here, we investigate how to leverage single-system contextuality to realize self-testing. We develop a robust self-testing protocol based on the simplest contextuality witness for the simplest contextual quantum system, the Klyachko-Can-Binicio\\u{g}lu-Shumovsky (KCBS) inequality for the qutrit. We establish a lower bound on the fidelity of the state and the measurements (to an ideal configuration) as a function of the value of the witness under a pragmatic assumption on the measurements we call the KCBS orthogonality condition. We apply the method in an experiment with randomly chosen measurements on a single trapped $^{40}{\\rm Ca}^+$ and near-perfect detection efficiency. The observed statistics allow us to self-test the system and provide the first experimental demonstration of quantum self-testing of a single system. Further, we quantify and report that deviations from our assumptions are minimal, an aspect previously overlooked by contextuality experiments.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2022-03-17T00:48:30.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "single quantum system",
      "simplest contextual quantum system",
      "measurements",
      "certifying individual quantum devices",
      "leverage single-system contextuality"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 6,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}