We propose a scheme which can simultaneously implement 1→ 2 optimal universal and phase-covariant quantum cloning in ion-trap systems.The required time for the whole procedure is short based on the resonant interaction,which is important in view of decoherence.Our scheme is feasible on the bases of present techniques.
We propose unified scheme to realize optimal 1→3 symmetric economical phase-covariant cloning (EPCC) and optimal 1→3 symmetric economical real state cloning (SERS) in the context of an ion-trap system. In this approach, the vibrational mode is not used to act as memory and the two cloners work without ancilla, thus it is likely to be much less sensitive to noise and decoherence. By adjusting tunable time parameters, our system can also perform optimal symmetric (asymmetric) universal quantum cloning and optimal symmetric (asymmetric) phase-covariant quantum cloning. Based on the advancement of experimental technique in an ion-trap system, the scheme is feasible and the symmetric economical state-dependent cloning is optimal.
We propose experimentally feasible schemes to implement the optimal asymmetric economical 1→2 and 1→3 phase-covariant cloning,which work without ancilla,in the context of ion-trap system.In these schemes the collective motional mode is initially prepared in the vacuum state |0.In the first scheme,we drive the first ion with a laser beam firstly,and then we map the motional mode state to the second ion.And in the second scheme,we drive two ions with different laser beams,and then we map the motional mode state to the third one.The schemes are based on resonant sideband excitation,thus they may be realized with current ion-trap techniques.