Quantum entanglement

“The two photons are entangled and according to local realism, their polarization planes should become independent... a typical EPR situation. Already in 1948, observations... agreed with quantum mechanics, not with local realism.”

“I'd like to think that the moon still exists, even if I'm not looking at it.”

“He [Albert Einstein] didn’t think the spooky action at a distance would be verified, but it was, He thought that was somehow unphysical. He presented this as an example of why quantum mechanics is probably wrong, but in fact it’s right.”

“When two systems, of which we know the states by their respective representation, enter into a temporary physical interaction due to known forces between them and when after a time of mutual influence the systems separate again, then they can no longer be described as before, viz., by endowing each of them with a representative of its own. I would not call that one but rather the characteristic trait of quantum mechanics.”

“There is a troubling weirdness about quantum mechanics. Perhaps its weirdest feature is entanglement, the need to describe even systems that extend over macroscopic distances in ways that are inconsistent with classical ideas.”