We can consider the spacetime diagram as having a causal structure, in fact, the axis labeled T can be considered the path for a clock that starts ticking at E. So at the point the measurements are made, assuming A and B are simultaneous, the clock's past lightcone intersects the future lightcone of E, and we have a causal diamond! So what? Well, the only quantum events or ops (aka Seth Lloyd) inside this causal diamond are the two polarization states of two distinct photons. The clock stops when the measurements are made. But in fact there are two clocks, one for each detector, the two photons are essentially synchronizing these clocks, the polarization measurements and random choice of angle correlate with the entanglement at E. You can take this experiment, an attempt to measure "speed of entanglement" via classical measurement of correlations, and upgrade it to a quantum teleportation experiment, with the role of synchronization signal handed over to a classical communication. Please Register or Log in to view the hidden image! Quantum information, yuh huh.