{
  "id": "1406.7300",
  "version": "v2",
  "published": "2014-06-27T20:06:01.000Z",
  "updated": "2014-10-24T19:13:33.000Z",
  "title": "Measurement and Control of Quasiparticle Dynamics in a Superconducting Qubit",
  "authors": [
    "Chen Wang",
    "Yvonne Y. Gao",
    "Ioan M. Pop",
    "Uri Vool",
    "Chris Axline",
    "Teresa Brecht",
    "Reinier W. Heeres",
    "Luigi Frunzio",
    "Michel H. Devoret",
    "Gianluigi Catelani",
    "Leonid I. Glazman",
    "Robert J. Schoelkopf"
  ],
  "comment": "8 pages with 4 figures for the main text, 13 pages with 11 figures for supplementary material",
  "categories": [
    "quant-ph",
    "cond-mat.mes-hall",
    "cond-mat.supr-con"
  ],
  "abstract": "Superconducting circuits have attracted growing interest in recent years as a promising candidate for fault-tolerant quantum information processing. Extensive efforts have always been taken to completely shield these circuits from external magnetic field to protect the integrity of superconductivity. Surprisingly, here we show vortices can improve the performance of superconducting qubits by reducing the lifetimes of detrimental single-electron-like excitations known as quasiparticles. Using a contactless injection technique with unprecedented dynamic range, we quantitatively distinguish between recombination and trapping mechanisms in controlling the dynamics of residual quasiparticles, and show quantized changes in quasiparticle trapping rate due to individual vortices. These results highlight the prominent role of quasiparticle trapping in future development of superconducting qubits, and provide a powerful characterization tool along the way.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2014-06-27T20:06:01.000Z",
      "abstract": "Superconducting circuits have attracted growing interest in recent years as a promising candidate for fault-tolerant quantum information processing. Extensive efforts have always been taken to completely shield these circuits from external magnetic field to protect the integrity of superconductivity. Surprisingly, here we show vortices can dramatically improve the performance of superconducting qubits by reducing the lifetimes of detrimental single-electron-like excitations known as quasiparticles. Using a contactless injection technique with unprecedented dynamic range, we directly demonstrate the power-law decay characteristics of the canonical quasiparticle recombination process, and show quantization of quasiparticle trapping rate due to individual vortices. Each vortex in our aluminium film shows a quasiparticle \"trapping power\" of $0.067\\pm0.005$ cm$^2$/s, enough to dominate over the vanishingly weak recombination in a modern transmon qubit. These results highlight the prominent role of quasiparticle trapping in future development of quantum circuits, and provide a powerful characterization tool along the way.",
      "comment": "7 pages with 4 figures for the main text, 12 pages with 9 figures for supplementary material",
      "journal": null,
      "doi": null
    },
    {
      "version": "v2",
      "updated": "2014-10-24T19:13:33.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "superconducting qubit",
      "quasiparticle dynamics",
      "measurement",
      "power-law decay characteristics",
      "canonical quasiparticle recombination process"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "doi": "10.1038/ncomms6836",
      "journal": "Nature Communications",
      "year": 2014,
      "month": "Dec",
      "volume": 5,
      "pages": 5836
    },
    "note": {
      "typesetting": "TeX",
      "pages": 8,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "adsabs": "2014NatCo...5E5836W"
    }
  }
}