FrediFizzx wrote:Gordon Watson wrote:A: Fred, you say this: "Following the notation used in the CH74 paper for eq. (4) then it is P12(a, b) = sin^2((a,b)/2) [under EPRB]." ???
I say: "Following the notation used in the CH74 paper for eq. (4) then P12(a, b) = (1/2) sin^2((a,b)/2) [under EPRB]." Reason: for me, P12(a, b) is the joint probability that both counts are triggered under the setting combination a and b. Further (and given in CH74), P1(a) is the marginal probability of Alice's detector being triggered under setting a; so it equals 1/2. So:
P12(a, b) = P1(a)P2(b|a) = (1/2) sin^2((a,b)/2); etc., as in my original derivation (above) re CH74.
NB: I'm no fan of the CH74 notation, but P2(b|a) -- a conditional probability -- is not here the same as P2(b) -- a marginal probability.
B: You say: "So I don't know how you are getting that from P2(a|b). P12 is the pairs probability count so P2 is a singles probability count."
I say: P12(a, b) is a joint probability. Under OPT it factors into P12(a, b) = P1(a)P2(b|a) = P2(b)P1(a|b). P2 is probability function associated with Bob's detector and we have two such: P2(b), a marginal probability; P2(b|a) a conditional probability; etc.
Note that I split this discussion to a new appropriate topic.
We are discussing the CH74 paper here so we should stick to their notation. P1, P2, and P12 are defined in their eq. (1) so P2 has to be a singles count (marginal probability?). You are just confusing the discussion by introducing something like P2(b|a).
Fred, with respect: You are confusing the discussion by not understanding P2(b|a) and by pointing to "errors" that are not.
My use of P2(b|a) is licensed by OPT. Given their (1), P2(b|a) CAN NEVER BE FALSE under OPT!
If you want to stick with their silly (2')* -- which is often false under OPT: and certainly false here -- then you are stuck with their silly results!
* Read their silly paragraph below (2'). Take note of their focus on AAD and their false extrapolation from common-sense (with no mention of the consequences of correlations: (2') even being false under some elementary classical correlations).
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