{
  "id": "2210.13406",
  "version": "v1",
  "published": "2022-10-24T17:04:29.000Z",
  "updated": "2022-10-24T17:04:29.000Z",
  "title": "Autonomous quantum error correction and fault-tolerant quantum computation with squeezed cat qubits",
  "authors": [
    "Qian Xu",
    "Guo Zheng",
    "Yu-Xin Wang",
    "Peter Zoller",
    "Aashish A. Clerk",
    "Liang Jiang"
  ],
  "categories": [
    "quant-ph"
  ],
  "abstract": "We propose an autonomous quantum error correction scheme using squeezed cat (SC) code against the dominant error source, excitation loss, in continuous-variable systems. Through reservoir engineering, we show that a structured dissipation can stabilize a two-component SC while autonomously correcting the errors. The implementation of such dissipation only requires low-order nonlinear couplings among three bosonic modes or between a bosonic mode and a qutrit. While our proposed scheme is device independent, it is readily implementable with current experimental platforms such as superconducting circuits and trapped-ion systems. Compared to the stabilized cat, the stabilized SC has a much lower dominant error rate and a significantly enhanced noise bias. Furthermore, the bias-preserving operations for the SC have much lower error rates. In combination, the stabilized SC leads to substantially better logical performance when concatenating with an outer discrete-variable code. The surface-SC scheme achieves more than one order of magnitude increase in the threshold ratio between the loss rate $\\kappa_1$ and the engineered dissipation rate $\\kappa_2$. Under a practical noise ratio $\\kappa_1/\\kappa_2 = 10^{-3}$, the repetition-SC scheme can reach a $10^{-15}$ logical error rate even with a small mean excitation number of 4, which already suffices for practically useful quantum algorithms.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2022-10-24T17:04:29.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "fault-tolerant quantum computation",
      "squeezed cat qubits",
      "error rate",
      "autonomous quantum error correction scheme",
      "dominant error"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}