Gómez Esteban S, Gómez Santiago, González Pablo, Cañas Gustavo, Barra Johanna F, Delgado Aldo, Xavier Guilherme B, Cabello Adán, Kleinmann Matthias, Vértesi Tamás, Lima Gustavo
Departamento de Física, Universidad de Concepción, 160-C Concepción, Chile.
Center for Optics and Photonics, Universidad de Concepción, 160-C Concepción, Chile.
Phys Rev Lett. 2016 Dec 23;117(26):260401. doi: 10.1103/PhysRevLett.117.260401. Epub 2016 Dec 20.
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.
对二能级系统的量子测量可以有两个以上的独立结果，在这种情况下，测量不是投影测量。这种一般类型的测量对于量子理论的一种操作方法至关重要，但到目前为止，测量的非投影特性只能通过已经假设实验装置部分的特定量子模型来进行实验验证。在这里，我们通过使用一种与设备无关的方法克服了这一限制。在一个关于偏振纠缠光子量子比特对的实验中，我们违反了一个类似贝尔的关联不等式超过8个标准差，该不等式对任何维度的所有双结果测量集都有效。我们将此与系统最好由两个量子比特描述的与设备无关的验证相结合，因此这构成了非投影量子测量的首次与设备无关的认证。
