{
  "id": "1204.6428",
  "version": "v1",
  "published": "2012-04-28T19:16:37.000Z",
  "updated": "2012-04-28T19:16:37.000Z",
  "title": "Time-Reversal Symmetry and Universal Conductance Fluctuations in a Driven Two-Level System",
  "authors": [
    "Simon Gustavsson",
    "Jonas Bylander",
    "William D. Oliver"
  ],
  "doi": "10.1103/PhysRevLett.110.016603",
  "categories": [
    "cond-mat.mes-hall",
    "cond-mat.supr-con",
    "quant-ph"
  ],
  "abstract": "In the presence of time-reversal symmetry, quantum interference gives strong corrections to the electric conductivity of disordered systems. The self-interference of an electron wavefunction traveling time-reversed paths leads to effects such as weak localization and universal conductance fluctuations. Here, we investigate the effects of broken time-reversal symmetry in a driven artificial two-level system. Using a superconducting flux qubit, we implement scattering events as multiple Landau-Zener transitions by driving the qubit periodically back and forth through an avoided crossing. Interference between different qubit trajectories give rise to a speckle pattern in the qubit transition rate, similar to the interference patterns created when coherent light is scattered off a disordered potential. Since the scattering events are imposed by the driving protocol, we can control the time-reversal symmetry of the system by making the drive waveform symmetric or asymmetric in time. We find that the fluctuations of the transition rate exhibit a sharp peak when the drive is time-symmetric, similar to universal conductance fluctuations in electronic transport through mesoscopic systems.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2012-04-28T19:16:37.000Z"
    }
  ],
  "analyses": {
    "subjects": [
      "72.15.Rn",
      "03.67.Lx",
      "05.40.Ca",
      "85.25.Cp"
    ],
    "keywords": [
      "universal conductance fluctuations",
      "time-reversal symmetry",
      "driven two-level system",
      "wavefunction traveling time-reversed paths",
      "driven artificial two-level system"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "publisher": "APS",
      "journal": "Physical Review Letters",
      "year": 2013,
      "month": "Jan",
      "volume": 110,
      "number": 1,
      "pages": "016603"
    },
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "adsabs": "2013PhRvL.110a6603G"
    }
  }
}