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 non-trivial assessment for devices performing unrealistically close to the ideal case. We overcome these difficulties by approaching self-testing with the semi-definite programming 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 CHSH 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 robust self-testing of non-maximally entangled two-qutrit states in the CGLMP scenario.
@article{arxiv.1406.7127,
title = {Robust and versatile black-box certification of quantum devices},
author = {Tzyh Haur Yang and Tamás Vértesi and Jean-Daniel Bancal and Valerio Scarani and Miguel Navascués},
journal= {arXiv preprint arXiv:1406.7127},
year = {2014}
}