Multi-atom entanglement engineering and phase-covariant quantum cloning with a single resonant interaction assisted by external driving

We propose a scheme to realize multi-atom entanglement and phase-covariant quantum cloning in a short-time manner possessing the advantage of its robustness with respect to parameter fluctuations. The process is achieved by externally driving the atoms to resonantly couple to the cavity mode. Compared to other strategies, such as the adiabatic or virtual-photon techniques, it provides a method which allows the relatively fast coherent manipulation.