I am having trouble wrapping my head around the sense in which entanglement is a physical phenomenon as opposed to a semantical byproduct of the bookkeeping involved in modern quantum theory. How can an entangled system be differentiated from a nonentangled system? If the answer is that such an identification is nonfeasible, then in what sense is entanglement an actual physical phenomenon?
I was under the impression that a particular entangled system is defined in terms of a particular waveform, which means that the choice of another waveform including, say, an additional particle off to the side, would imply that the entanglement -- which is supposed to be the behaviour being described, not the theory used to describe it -- actually changes. So, substitution of separate waveforms for each component of the entanglement would imply that entanglement is not present. How would this be false in a way different from the inaccuracies present in any other choice of waveform?
I was under the impression that a particular entangled system is defined in terms of a particular waveform, which means that the choice of another waveform including, say, an additional particle off to the side, would imply that the entanglement -- which is supposed to be the behaviour being described, not the theory used to describe it -- actually changes. So, substitution of separate waveforms for each component of the entanglement would imply that entanglement is not present. How would this be false in a way different from the inaccuracies present in any other choice of waveform?