Bell measurement rules out supraquantum correlations (1802.09510v2)

Abstract: The so called bipartite non-signaling boxes are systems whose statistics is constrained solely by the principle of no instantaneous signaling between distant locations. Such systems can exhibit much stronger correlations than those admitted by quantum mechanics. Inspired by quantum logic approach of Tylec and Ku\'{s}, J. Phys. A: Math. Theor. 48 (2015) 505303, we consider non-signaling boxes with three inputs per party, and extend the set of measurements with just a single {\it global} measurement - one that mimics quantum two-party Bell measurement. We then show that this seemingly mild extension completely rules out supraquantum correlations: the resulting system admits precisely quantum mechanical correlations of two qubits. We also consider non-maximally entangled measurements, obtaining interpolation between quantum and full no-signaling theory. Our study paves a way to a general programme of amending no-signaling theories with some measurements inherited from quantum mechanics, leading to various interpolations between non-signaling boxes and quantum mechanics.