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rede96
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Forgive the layman type question but I was doing some reading on Bell's inequality and how it disproves the hidden variable hypothesis in entanglement.
The example I looked at was from YouTube
I understand the principle of how bell's theorem works and how the tests done on polarisation of photons gave a result that was wasn't possible under Bell's inequality. But I was still sort of confused.
In the example for Bell's inequality, the author of the video uses an example where kids can be wearing hats, scarfs and gloves to represent the different 'states' that a child can be in. Then went on to explain how 'Alice' and 'Bob', would test entangled photons (which should be polarized in the exact same way) through randomly selected polarization screens. (Sorry if my terminology is crap!)
What I don't get is that if I imagine a mother with twins who say puts a hat on each twin, then if I test the twins to see if they wearing a wearing a hat. scarf or glove, then in my example, the results would always show 'hats' for both those twins.
But as I understand it, if a photon is polarised in say a vertical direction, then if I test using an a certain angle of polarization, then there is only a certain probability that a photon will pass through the screen.
So if there are a pair of entangled photons, there is the same probability that anyone of them would pass through the angled polarisation. So even though they are both polarized in the same direction, as I understand it, wouldn't there still be an independent probability for each photon to pass through the angled polarization screen? So one may pass through the angled screen and one might not.
This is different than with the twins wearing hats, as any test has to show either both are, or both are not wearing hats.
Which is a very long winded way of saying is Bell's inequality really relevant for entanglement?
Hope that makes sense.
The example I looked at was from YouTube
I understand the principle of how bell's theorem works and how the tests done on polarisation of photons gave a result that was wasn't possible under Bell's inequality. But I was still sort of confused.
In the example for Bell's inequality, the author of the video uses an example where kids can be wearing hats, scarfs and gloves to represent the different 'states' that a child can be in. Then went on to explain how 'Alice' and 'Bob', would test entangled photons (which should be polarized in the exact same way) through randomly selected polarization screens. (Sorry if my terminology is crap!)
What I don't get is that if I imagine a mother with twins who say puts a hat on each twin, then if I test the twins to see if they wearing a wearing a hat. scarf or glove, then in my example, the results would always show 'hats' for both those twins.
But as I understand it, if a photon is polarised in say a vertical direction, then if I test using an a certain angle of polarization, then there is only a certain probability that a photon will pass through the screen.
So if there are a pair of entangled photons, there is the same probability that anyone of them would pass through the angled polarisation. So even though they are both polarized in the same direction, as I understand it, wouldn't there still be an independent probability for each photon to pass through the angled polarization screen? So one may pass through the angled screen and one might not.
This is different than with the twins wearing hats, as any test has to show either both are, or both are not wearing hats.
Which is a very long winded way of saying is Bell's inequality really relevant for entanglement?
Hope that makes sense.