{
  "id": "1408.6763",
  "version": "v1",
  "published": "2014-08-28T16:04:22.000Z",
  "updated": "2014-08-28T16:04:22.000Z",
  "title": "Experimental observation of Hardy-like quantum contextuality",
  "authors": [
    "Breno Marques",
    "Johan Ahrens",
    "Mohamed Nawareg",
    "Adan Cabello",
    "Mohamed Bourennane"
  ],
  "comment": "17 pages, 3 figures",
  "categories": [
    "quant-ph"
  ],
  "abstract": "Contextuality is a fundamental concept for understanding quantum probabilities and the origin of the power of quantum systems for computation and information processing. A natural question is: Which is the simplest and cleanest version of quantum contextuality? It has been very recently found that there is a version that is analog to \"the simplest and cleanest\" version of quantum non-locality, but only requires single three-level quantum systems (qutrits) rather than composite systems. Here we report the first experimental observation of this \"Hardy-like\" quantum contextuality. We measured the correlations between the outcomes of five combinations of two compatible measurements performed sequentially, in any possible order, on heralded photonic path-encoded qutrits. The experiment adopts a novel configuration which allows for performing two sequential measurements on the same photon with a high fidelity and allows for observing the independence of the correlations with respect to the order in which measurements are performed. The experimental results match the conditions needed to define a Hardy-like argument and the predictions of quantum theory. In addition, they violate the relevant non-contextuality inequality, even when the non-contextual bound is corrected to take into account experimental imperfections. The experimental observation of this form of quantum contextuality is of fundamental importance, since it connects the Kochen-Specker theorem with the simplest non-contextuality inequality. In addition, the method introduced here opens the door to applications requiring sequential quantum measurements on photonic systems.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2014-08-28T16:04:22.000Z"
    }
  ],
  "analyses": {
    "subjects": [
      "03.65.Ta",
      "03.65.Ud",
      "03.67.Mn",
      "42.50.Xa"
    ],
    "keywords": [
      "experimental observation",
      "hardy-like quantum contextuality",
      "applications requiring sequential quantum measurements",
      "single three-level quantum systems",
      "simplest non-contextuality inequality"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "doi": "10.1103/PhysRevLett.113.250403",
      "journal": "Physical Review Letters",
      "year": 2014,
      "month": "Dec",
      "volume": 113,
      "number": 25,
      "pages": 250403
    },
    "note": {
      "typesetting": "TeX",
      "pages": 17,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "adsabs": "2014PhRvL.113y0403M"
    }
  }
}