Greg Egan on Nostr: It’s worth stressing that when Alice makes her measurement on particles X and A, ...

It’s worth stressing that when Alice makes her measurement on particles X and A, all four outcomes always have equal probability of 1/4. Despite the fact that the precise state of particle X depends on α and β, those parameters have absolutely no effect on the probability of her finding X and A jointly in each of the \(e_nn\).

So, as far as Alice is concerned, she has just generated a random 2-bit number. But to Bob, it contains precisely what he needs to transform his particle B into a state that contains all the information that Alice previously could have extracted from particle X.