>>11265273You don’t just choose two particles.
They need to be related in some way where the state of one is affected by the state of the other.
An example (that isnt real) is if you generate two photons from nothing. One particle would have +1 spin, and the other would have -1 spin (due to how spin is conserved).
However, you don’t know what the spin of both particles are, and so they are in a superposition of states. When you measure just one particle, the superposition of both photons collapse, because the inherent relationship between the two let’s you know what the spin of the other photon is.
