I am confused by the role of photon polarisation in Bell inequality experiments.(adsbygoogle = window.adsbygoogle || []).push({});

The original logic of EPR as I understand it is based on the HUP such that QM predicts that

measurement of momentum on one particle should affect the measurement of position

of the other particle. Yet across large distances this would required superluminal communication. EPR

I can see that measurement of spin is a form of angular momentum but AFAIK bell inequality

experiments do not measure corresponding position, they measure correlations between

spin measurements.

So I don't understand the involvement of the HUP in entangled pairs. Even worse, I am unsure whether photon polarisation has anything to do with angular momentum at all and hence is even less related to the HUP.

In short, how does the HUP relate to measurement of singlet states and what is the logic behind redesigning EPR experiments from position/momentum uncertainty to correlations between spin or polarisation?

Thanks for any help

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# Bell inequality experiments and photon polarisation issue

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