Conditions for the confirmation of three-particle nonlocality

The notion of genuine three-particle nonlocality introduced by Svetlichny Phys. Rev. D 35 10, 3066 (1987)] is discussed. Svetlichny’s inequality, which can distinguish between genuine three-particle and three-particle nonlocality that is based on underlying two-particle nonlocality, is analyzed by reinterpreting it as a frustrated network of correlations. Its quantum-mechanical maximum violation is derived and a situation is presented that produces the maximum violation. We show that recent beautiful experiments to demonstrate nonlocality for a three-party state by the GHZ paradox, although demonstrating nonlocality, do not allow any violation of the Svetlichny inequality. However, we show that with only minor modifications to the measurements performed, the experiments would be far more powerful and able to demonstrate genuine three-party nonlocality.