So, I decided to refresh my knowledge on the subject and found some interesting information:
- First a very clear and nice page from Physics FAQ about Bell Inequality and EPR.
- Of course Wikipedia on Bell Inequality
- And the “push to the limit” 10km experiment
After reading all this, I got the feeling that closing all the loopholes is a necessary and quite fun adventure. But to keep believing that there is some hidden local variables theory that can explain Quantum Mechanics, is like saying OJ Simpson did not kill his wife!
To keep hanging to the smallest piece of evidence that keep the world flat, when all the other experiments shows you the opposite, seems like despair in letting the world be!
What's funny for me about this “hidden-local-variables” argument is that the duality wave-particle is already breaking it! I was looking for the “biggest photon” :) ever created and found that the army created some photons the size of the earth! It's quite nice to imagine a double-slit experiment where the holes are on each side of the earth!
The other sets of experiments that are truly amazing about quantum state are from the Quantum Computing research. They start with 2 ions excited by a laser and so 2 separated Quantum State (ions + emitted photon) are created. Then by entangling the photons the ions are entangled. Since the ions are in “a box”, you could actually carry them around (usually one by Alice and the other by Bob :), and whenever you feel like it (a cat died) you can detect your ions state and break the entanglement.
I “kind of” understand the despair of finding a local deterministic solution to this, but I find it a lot more fun to let go.
Personally, I made peace with Quantum Mechanics when I started to give the Quantum State all the freedom he has!
I mean, those guys down there, have spin, can change color, and each time they do it, they can avoid each other (Pauli exclusion), just like that!
Do I sound like a crackpot when I say: Those little guys, have way more freedom than our 3 + 1 dimensional spacetime?
So, if a quantum state with all the particles that are part of it, have all this freedom, staying connected with all your friends does not look so difficult!
For me, in the sentence “Spooky action at distance!” the problem is not that we don't understand how QM is “acting”, but we don't know what “distance” means for those small little guys.
I was trying to find a theory that uses extra-dimension but with metrics that make the measure of “a distance” far from our standard square root of sum of square thing. Is there one?
So, our universe is “non-local” for our 3+1 vision of the world, but it may be totally “local” for all the “Quantum States” observers?