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I get conflicting answers but as far as I can tell, quantum mechanics predicts photon correlations would be 50 percent of the time. Is this correct and would correlations of entangled electrons be the same?

What would be a good article or paper that would describe these percentages best? Thanks

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  • $\begingroup$ all I’m asking is what does quantum mechanic’s predict? $\endgroup$
    – Bill Alsept
    Commented Dec 15, 2017 at 4:41
  • $\begingroup$ Come on! I took the time to re-edit and simplify the question. Why not answer the question instead of down voting? Is this question answerable or not? $\endgroup$
    – Bill Alsept
    Commented Dec 15, 2017 at 19:12
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    $\begingroup$ would be what 50% of the time? $\endgroup$
    – Kyle Kanos
    Commented Dec 16, 2017 at 18:32
  • $\begingroup$ @KyleKanos if each particle was randomly tested at different angles, then Alice and Bob should correlate with the same reading 50 percent of the time. When I say correlated I mean each detector would register the same thing 50 percent of the time. That could be as simple as each one is detected or each one is not detected. Or maybe that each one goes through detectors set at the same angle. Overall no matter how you set the angle of the detectors I believe quantum mechanics predicts the correlations will happen 50 percent of the time. It’s that percentage that I was trying to confirm. $\endgroup$
    – Bill Alsept
    Commented Dec 16, 2017 at 19:01

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Your question is somewhat unclear, but I agree, people should try to answer, or help correct the question instead of down voting.

Anyway, part of your question is answerable - There would not be any difference in prediction for photons vs electrons. So, if the prediction for photons is 50%, it would be same for electrons.

Rest of the question does not seem to be answerable to me.

The correlation percent between particles of entangled pairs, taking spin as an example, and taking simplest case/state, depends upon the relative angle at with the two particles of the pair are measured. That correlation is "square of sin(theta/2)" where theta is the angle between the axis of measurement of the two particles. This way, if you measure them along perpendicular lines, then the correlation percent is 50. As you specified no angle, your question is not answerable. More over, various states also play role to complicate it further. Please do some reading/watching on it.

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  • $\begingroup$ @BillAlsept: The correlation percent between particles of entangled pairs, taking spin as an example, and taking simplest case/state, depends upon the relative angle at with the two particles of the pair are measured. That correlation is "square of sin(theta/2)" where theta is the angle between the axis of measurement of the two particles. This way, if you measure them along perpendicular lines, then the correlation percent is 50. As you specified no angle, your question is not answerable. More over, various states also play role to complicate it further. Please do some reading/watching on it. $\endgroup$
    – kpv
    Commented Dec 15, 2017 at 22:18
  • $\begingroup$ I have read a lot about this and your answer is kind of what I’m talking about. I know that the individual particles detections are related to the angle. Depending on the experiment that could mean a reading of up or down or simply detection or not. My question is not about that. My question is about how often the two particles are correlated ( having the same detection or reading). That percentage can and has been answered but not to clearly. I believe it is 50 percent but I would like to have it confirmed. Thanks $\endgroup$
    – Bill Alsept
    Commented Dec 15, 2017 at 22:54
  • $\begingroup$ Yes, when they are both up, or both down, that means they are correlated. This correlation depends upon what relative angle you measure them at. If you measure them (Bell's state) at same angle, then if one is up, other will be down, they will always have opposite outcome, i.e. 0% correlation. But if you measure one at 0 degree and the other at 90 degrees then they will be 50% times same outcome and 50% times opposite outcome - i.e 50% correlated. $\endgroup$
    – kpv
    Commented Dec 15, 2017 at 23:43

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