Quantum copying: A review
Mark S. Hillery · DOAJ (DOAJ: Directory of Open Access Journals) · 2000
Quantum information is stored in two-level quantum systems known as qubits. The no-cloning theorem states that the state of an unknown qubit cannot be copied. This is in contrast to classical information which can be copied. If one drops the requirement that the copies be perfect it is possible to design quantum copiers. This paper presents a short review of the theory of quantum copying.