Figure 2
From: Answering Mermin’s challenge with conservation per no preferred reference frame
Alice and Bob making spin measurements on a pair of spin-entangled particles with their Stern–Gerlach (SG) magnets and detectors in the xz-plane. Here Alice and Bob’s SG magnets are not aligned so these measurements represent different reference frames. Since their outcomes satisfy Dakic and Brukner’s Axiom 1 in all reference frames and satisfy explicit conservation of spin angular momentum in the same reference frame, they can only satisfy conservation of spin angular momentum on average in different reference frames. This “average-only” conservation corresponds to the “elliptope constraint” of Janas et al.7.
