Entanglement is Necessary for Emergent Classicality in All Physical Theories.

@article{Richens2017EntanglementIN,
  title={Entanglement is Necessary for Emergent Classicality in All Physical Theories.},
  author={Jonathan G. Richens and John H Selby and Sabri W Al-Safi},
  journal={Physical review letters},
  year={2017},
  volume={119 8},
  pages={080503}
}
One of the most striking features of quantum theory is the existence of entangled states, responsible for Einstein's so called "spooky action at a distance." These states emerge from the mathematical formalism of quantum theory, but to date we do not have a clear idea of the physical principles that give rise to entanglement. Why does nature have entangled states? Would any theory superseding classical theory have entangled states, or is quantum theory special? One important feature of quantum… CONTINUE READING