{
  "id": "1311.2197",
  "version": "v2",
  "published": "2013-11-09T18:45:47.000Z",
  "updated": "2014-01-29T12:52:13.000Z",
  "title": "Phonon-Mediated Decay of Singlet-Triplet Qubits in Double Quantum Dots",
  "authors": [
    "Viktoriia Kornich",
    "Christoph Kloeffel",
    "Daniel Loss"
  ],
  "comment": "18 pages main article, 6 figures",
  "journal": "Phys. Rev. B 89, 085410 (2014)",
  "doi": "10.1103/PhysRevB.89.085410",
  "categories": [
    "cond-mat.mes-hall"
  ],
  "abstract": "We study theoretically the phonon-induced relaxation ($T_1$) and decoherence times ($T_2$) of singlet-triplet qubits in lateral GaAs double quantum dots (DQDs). When the DQD is biased, Pauli exclusion enables strong dephasing via two-phonon processes. This mechanism requires neither hyperfine nor spin-orbit interaction and yields $T_2 \\ll T_1$, in contrast to previous calculations of phonon-limited lifetimes. When the DQD is unbiased, we find $T_2 \\simeq 2 T_1$ and much longer lifetimes than in the biased DQD. For typical setups, the decoherence and relaxation rates due to one-phonon processes are proportional to the temperature $T$, whereas the rates due to two-phonon processes reveal a transition from $T^2$ to higher powers as $T$ is decreased. Remarkably, both $T_1$ and $T_2$ exhibit a maximum when the external magnetic field is applied along a certain axis within the plane of the two-dimensional electron gas. We compare our results with recent experiments and analyze the dependence of $T_1$ and $T_2$ on system properties such as the detuning, the spin-orbit parameters, the hyperfine coupling, and the orientation of the DQD and the applied magnetic field with respect to the main crystallographic axes.",
  "revisions": [
    {
      "version": "v2",
      "updated": "2014-01-29T12:52:13.000Z"
    }
  ],
  "analyses": {
    "subjects": [
      "73.21.La",
      "71.70.Ej",
      "03.67.Lx",
      "71.38.-k"
    ],
    "keywords": [
      "singlet-triplet qubits",
      "phonon-mediated decay",
      "lateral gaas double quantum dots",
      "two-phonon processes",
      "magnetic field"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "publisher": "APS",
      "journal": "Physical Review B",
      "year": 2014,
      "month": "Feb",
      "volume": 89,
      "number": 8,
      "pages": "085410"
    },
    "note": {
      "typesetting": "TeX",
      "pages": 18,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "adsabs": "2014PhRvB..89h5410K"
    }
  }
}