Three-qubit quantum error-correction scheme based on quantum cloning

This Letter presents a three-qubit quantum error correction scheme that adopts the optimal universal 1->2 quantum cloning transformation U to encode an unknown state vertical bar φ> vertical bar 0> vertical bar 0> into a three-qubit state U vertical bar φ> vertical bar 0> vertical bar 0>. The encoded state could protect against collective decoherences that any two qubits in a three-qubit system are affected by either phase error or bit flip error, or simultaneously affected by both of them. To recover the original unknown state, we just need to perform a Bell measurement on the first two qubits and rotate the third qubit along a suitable axis. Specially, our scheme for the first time shows that quantum cloning is useful for quantum error correction