Scheme for the implementation of the optimal economical phase-covariant quantum cloning machine with SQUID qubits in cavity QED

We propose a scheme to realize the optimal economical 1→21→2 phase-covariant quantum cloning machine (QCM) in 2 dimension with superconducting quantum interference device (SQUID) qubits in a microwave cavity. In our scheme, two-SQUID qubits are fixed into a microwave cavity by adiabatic passage method for their manipulation. Using this method, we can realize the optimal phase-covariant QCM only by one step.