All-purpose quantum cloning machine

We present an approach to realize an all-purpose quantum cloning machine and represent how to realize it using SQUID qubit. In this approach, single-qubit rotation operations and two-qubit operations are adjusted to serve the cloning manipulation. Through changing the time parameters, optimal symmetric (asymmetric) 1 → 2 universal quantum cloning, optimal symmetric (asymmetric) 1 → 2 phase-covariant cloning and optimal symmetric 1 → 3 economical phase-covariant cloning can be performed.