title: Robust and versatile black-box certification of quantum devices.
abstract: Self-testing refers to the fact that, in some quantum devices, both states and measurements can be assessed in a black-box scenario, on the sole basis of the observed statistics, i.e., without reference to any prior device calibration. Only a few examples of self-testing are known, and they just provide nontrivial assessment for devices performing unrealistically close to the ideal case. We overcome these difficulties by approaching self-testing with the semidefinite programing hierarchy for the characterization of quantum correlations. This allows us to improve dramatically the robustness of previous self-testing schemes; e.g., we show that a Clauser-Horne-Shimony-Holt violation larger than 2.57 certifies a singlet fidelity of more than 70%. In addition, the versatility of the tool brings about self-testing of hitherto impossible cases, such as the robust self-testing of nonmaximally entangled two-qutrit states in the Collins-Gisin-Linden-Massar-Popescu scenario.
authors.affiliation: Centre for Quantum Technologies, National University of Singapore, 3 Science drive 2, Singapore 117543, Singapore.
authors.forename: Tzyh Haur
authors.initials: TH
authors.lastname: Yang
authors.affiliation: Institute for Nuclear Research, Hungarian Academy of Sciences, P.O. Box 51, H-4001 Debrecen, Hungary.
authors.forename: Tamás
authors.initials: T
authors.lastname: Vértesi
authors.affiliation: Centre for Quantum Technologies, National University of Singapore, 3 Science drive 2, Singapore 117543, Singapore.
authors.forename: Jean-Daniel
authors.initials: JD
authors.lastname: Bancal
authors.affiliation: Centre for Quantum Technologies, National University of Singapore, 3 Science drive 2, Singapore 117543, Singapore and Department of Physics, National University of Singapore, 2 Science drive 3, Singapore 117542, Singapore.
authors.forename: Valerio
authors.initials: V
authors.lastname: Scarani
authors.affiliation: School of Physics, University of Bristol, Tyndall Avenue, Bristol BS8 1TL, United Kingdom.
authors.forename: Miguel
authors.initials: M
authors.lastname: Navascués