- #141

Lord Crc

- 343

- 47

Let's say Alice sets her detector to theta degrees and say Bob also sets his to theta degrees. If photons A and D are entangled then they will measure the same 100% of the time (or 0% if the photons are anti-correlated). Now, if A and D are NOT entangled, then, since the pairs AB and CD are independent, they would measure the same 50% of the time (ie independent uniformly random distributions).

Assuming the above is correct, then I fail to see how Charlie's information is needed for Alice and Bob to figure out if the photons are entangled. That is, I understand they can't do so on a single pair basis, but assume that Charlie ensures that the pairs are always entangled. Then how is this different from the situation where Charlie doesn't exist and Alice and Bob performs the measurements on a single pair of entangled photons?

However if it results in the same situation as a single pair measurement, then it would seem that Charlie has no free will, assuming he doesn't change his mind too often :)

Due to this I assume that I missed a turn somewhere, invalidating my subsequent assumptions. Anyone care to shed some light? Thanks in advance.