PREPARATION AND MANIPULATION OF W-CLASS ENTANGLED STATES: APPLICATIONS TO QUANTUM-INFORMATION PROCESSING
We propose a cavity-quantum-electrodynamics scheme for one-step generation of the special configuration of W-class state [Formula: see text] which can implement deterministic teleportation, superdense coding, quantum-information splitting, and phase-covariant telecloning. We also present a method for one-step realization of a nontrivial unitary transformation [Formula: see text] which can transform a standard W state into a fully separable state. The [Formula: see text] operation plays a key role in recently proposed quantum-information processing tasks. Both the schemes are robust against decoherence. In addition, they can endure the error of controlling the interaction time between atoms and cavity. Our ideas can also be generalized to other systems.