2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/163654We present a new and feasible test proving quantum contextuality in four-dimensional Hiltbert space. In our scheme, a contradiction between quantum mechanics and noncontextual hidden variables is revealed through the measurement statistics of two joint measurements of an ensemble of non-entangled qubits. The origin of nonclassicality is fully attributed to the measurement process. Quantum optical realization using photon pairs and linear optics are presented.4 pages, 2 figures, RevTeX, revised introductionQuantum Physicstext