Experimental Test of the Quantum Violation of the Noncontextuality Inequalities for the n-Cycle Scenario

The inequalities that separate contextual from noncontextual correlations for the n-cycle scenario (consisting of n dichotomic observables Oj, with j = 0, ..., n-1 and such that Oj and Oj+1 are jointly measurable) have been recently identified [arXiv:1206.3212 (2012)]. Here we report the results of an experiment designed to reach the maximum quantum violation of these inequalities for any even number of observables ranging from 4 to 14. The four dimensional Hilbert space required for the test was spanned by two photonic qubits encoded in the transversal path of photon pairs, and the joint measurability of the observables is guaranteed by measuring correlations between observables from different modes. Our results show contextual correlations as predicted by quantum mechanics.