Does the no-cloning theorem say that 2 systems can't exists anywhere in the universe that have exactly the same state, or just that you can't achieve that by cloning but you can achieve it by some other means?

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    $\begingroup$ No-cloning means there is no deterministic (unitary) process which can clone an unknown quantum state. $\endgroup$ – gautampk Jun 6 '17 at 15:40
  • $\begingroup$ Related/possible duplicate: physics.stackexchange.com/q/310075/50583 $\endgroup$ – ACuriousMind Jun 6 '17 at 15:41
  • $\begingroup$ @ACuriousMind Thank you, that answers my question. You can close it as duplicate, or should I just delete it? $\endgroup$ – sashoalm Jun 6 '17 at 15:44
  • $\begingroup$ Minuteearth has a really good explanation of the No-Cloning Theorem. $\endgroup$ – Emilio Pisanty Jun 6 '17 at 17:01