Device-Independent Certification of a Nonprojective Qubit Measurement
Abstract
Quantum measurements on a two-level system can have more than two independent outcomes, and in this case, the measurement cannot be projective. Measurements of this general type are essential to an operational approach to quantum theory, but so far, the nonprojective character of a measurement can only be verified experimentally by already assuming a specific quantum model of parts of the experimental setup. Here, we overcome this restriction by using a device-independent approach. In an experiment on pairs of polarization-entangled photonic qubits we violate by more than 8 standard deviations a Bell-like correlation inequality that is valid for all sets of two-outcome measurements in any dimension. We combine this with a device-independent verification that the system is best described by two qubits, which therefore constitutes the first device-independent certification of a nonprojective quantum measurement.
Keywords
Cite
@article{arxiv.1604.01417,
title = {Device-Independent Certification of a Nonprojective Qubit Measurement},
author = {Esteban S. Gómez and Santiago Gómez and Pablo González and Gustavo Cañas and Johanna F. Barra and Aldo Delgado and Guilherme B. Xavier and Adán Cabello and Matthias Kleinmann and Tamás Vértesi and Gustavo Lima},
journal= {arXiv preprint arXiv:1604.01417},
year = {2016}
}
Comments
6 pages, 3 figures. Published version