Abstract:
The result that quantum nonlocality is causal because it cannot be used to transfer classical information across spacelike intervals is extended to entangled n-partite systems (n2). We show that correlations between any m (0<m<n) of the subsystems is independent of unitary operations performed on any other k subsystems and/or (projective, nondegenerate) measurement operations performed on any other l (n−ml,k<n) subsystems. This corroborates the peaceful coexistence of quantum mechanics and special relativity, and is in keeping with the understanding that the total information in an entangled system is locally inaccessible.