Scheme to implement the optimal asymmetric economical 1→3 phase-covariant cloning in cavity QED

We propose an experimentally feasible scheme to implement the optimal asymmetric economical 1→3 phase-covariant cloning,which works without ancilla,based on cavity QED.In our scheme,two of the three atoms simultaneously interact with a cavity field and they are driven by classical fields.The scheme is insensitive to the cavity field states and the cavity decay.Therefore,it may be realized in experiment.