{
  "id": "1403.4228",
  "version": "v4",
  "published": "2014-03-17T19:40:35.000Z",
  "updated": "2015-04-13T17:46:06.000Z",
  "title": "Consistency Tests of Classical and Quantum Models for a Quantum Annealer",
  "authors": [
    "Tameem Albash",
    "Walter Vinci",
    "Anurag Mishra",
    "Paul A. Warburton",
    "Daniel A. Lidar"
  ],
  "comment": "36 pages, 36 figures. v2: Addresses the issues raised in arXiv:1404.6499. v3. Paper reorganized for clarity of presentation, but results have not change since v2. v4: Updated title, author order, abstract, and manuscript to match published version",
  "journal": "Phys. Rev. A 91, 042314 (2015)",
  "doi": "10.1103/PhysRevA.91.042314",
  "categories": [
    "quant-ph"
  ],
  "abstract": "Recently the question of whether the D-Wave processors exhibit large-scale quantum behavior or can be described by a classical model has attracted significant interest. In this work we address this question by studying a 503 qubit D-Wave Two device in the \"black box\" model, i.e., by studying its input-output behavior. Our work generalizes an approach introduced in Boixo et al. [Nat. Commun. 4, 2067 (2013)], and uses groups of up to 20 qubits to realize a transverse Ising model evolution with a ground state degeneracy whose distribution acts as a sensitive probe that distinguishes classical and quantum models for the D-Wave device. Our findings rule out all classical models proposed to date for the device and provide evidence that an open system quantum dynamical description of the device that starts from a quantized energy level structure is well justified, even in the presence of relevant thermal excitations and a small value of the ratio of the single-qubit decoherence time to the annealing time.",
  "revisions": [
    {
      "version": "v3",
      "updated": "2014-07-18T19:12:34.000Z",
      "title": "Distinguishing Classical and Quantum Models for the D-Wave Device",
      "abstract": "Recently the question of whether the D-Wave processors exhibit large-scale quantum behavior or can be described by a classical model has attracted significant interest. In this work we address this question by studying a 503 qubit D-Wave Two device as a \"black box\", i.e., by studying its input-output behavior. Our work generalizes an approach introduced in Boixo et al., Nature Comm. 4, 3067 (2013), and uses groups of up to 20 qubits to realize a transverse Ising model evolution with a ground state degeneracy whose distribution acts as a sensitive probe that distinguishes classical and quantum models for the D-Wave device. Our findings rule out all classical models proposed to date for the device and provide evidence that an open system quantum dynamical description of the device that starts from a quantized energy level structure is well-justified, even in the presence of relevant thermal excitations and a small value of the ratio of the single-qubit decoherence time to the annealing time.",
      "comment": "36 pages, 36 figures. v2: Addresses the issues raised in arXiv:1404.6499. v3. Paper reorganized for clarity of presentation, but results have not change since v2",
      "journal": null,
      "doi": null,
      "authors": [
        "Walter Vinci",
        "Tameem Albash",
        "Anurag Mishra",
        "Paul A. Warburton",
        "Daniel A. Lidar"
      ]
    },
    {
      "version": "v4",
      "updated": "2015-04-13T17:46:06.000Z"
    }
  ],
  "analyses": {
    "subjects": [
      "03.67.Ac",
      "03.65.Yz"
    ],
    "keywords": [
      "d-wave device",
      "quantum models",
      "distinguishing classical",
      "open system quantum dynamical description",
      "ground state degeneracy"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "publisher": "APS",
      "journal": "Physical Review A",
      "year": 2015,
      "month": "Apr",
      "volume": 91,
      "number": 4,
      "pages": "042314"
    },
    "note": {
      "typesetting": "TeX",
      "pages": 36,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "adsabs": "2015PhRvA..91d2314A"
    }
  }
}