Entangled Material Recently I saw the case of creating two entangled electrons with opposite spins from the Higgs boson (which has no spin). The electron spins are always opposite to equal zero as a sum - conserving the Higgs zero spin. So we always create opposites. Why would anyone find that remarkable? People have expressed amazement about the fact that the result can be guaranteed - even before light would have a chance to travel the distance. I don’t understand. If the result is always AB or BA depending who measures which why would this be quirky in any way and why would anyone suspect communication between the electrons?
 A: The term "quantum entanglement exists" is a subset of the term "there exists a single quantum mechanical wavefunction describing the system".
If you know the wavefunction, i.e. have a mathematical description of it, the theory of quantum mechanics has constraints on quantum numbers and their conservation, so quantum numbers are "entangled" because there exists a single wavefunction describing the system, that is all.
Let us take a simple example, the pi0 decay. It decays into two photons/gammas. The pi0 has spin zero. From conservations of quantum numbers ( in this case angular momentum conservation) in the decay wavefunction, one of the photons must have spin +1 and the other -1 the direction being the direction of their motion.
Once the decay has happened and there are no interactions, the spins are unknown for the experimenter, but they are defined by the wavefunction.
If I measure one in the lab and the other reach Alpha Centauri, I know its spin by having measured the one in the lab and using angular momentum conservation.
What people get confused with is with who has the information.
The information is not shared by the photons, the information is in the head of the experimenter, who sits in the lab.
How do we know this is true? Because we have validated quantum mechanical theory with innumerable experiments, trust mathematics, and extrapolate, all the information here in the lab.
A: Simply put a quantum entangled system will always "beat" a classical one with the goal of correlating experiment outcomes. Regardless of the type of correlation or strategy taken by the classical system, assuming no communication is allowed once the two objects are separated. How does this "enchanced" correlation work precisely? We aren't sure but we often describe it as spooky action at a distance (still may still preserve relativity). We know this because Bell's and others' experiments ruled out local hidden variables as a possibility. There could still be superdeterminism (if you don't assume independence of experimenters as we have), pilot-wave, qbism, or other nonlocal theories but they are seen as more 'extreme' than conventional ways of teaching qm, and have their own problems.
