Scheme to implement optimal asymmetric economical 1→3 phase-covariant telecloning via cavity QED

We propose an experimentally feasible scheme to implement the optimal asymmetric economical 1→3 phasecovariant telecloning protocol, which works without ancilla, based on cavity quantum electrodynamics （QED）. The scheme is insensitive to the cavity field states and the cavity decay. In the telecloning process, the cavity is only virtually excited, it greatly prolongs the efficient decoherent time. Therefore, the scheme may be experimentally realized in the field of current cavity QED techniques.

Remote Quantum-Information Concentration: Reversal of Ancilla-Free Phase-Covariant Telecloning

Telecloning and its reverse process, referred to as remote quantum-information concentration (RQIC), have been attracting considerable interest because of their potential applications in quantum-information processing. The previous RQIC protocols were focused on the reverse process of the optimal universal telecloning. We here study the reverse process of ancilla-free phase-covariant telecloning (AFPCT). It is shown that the quantum information originally distributed into two spatially separated qubits from a single qubit via the optimal AFPCT procedure can be remotely concentrated back to a single qubit with a certain probability by using an asymmetric W state as the quantum channel.

Controlled Telecloning and Teleflipping for One-Qubit Pure States

We propose a scheme for realizing controlled 1→2 telecloning and 1 →1 teleflipping for one-qubit pure states via a quantum network including N agents. The quantum operations used in the information-transmission process are just only one Bell-state measurement, and a series of single-qubit operation. It is shown that the fidelities of the controlled telecloning and teleflipping are independent of the initial states and reach their optimal values of 5/6 and 2/3 respectively on the condition that all the agents collaborate. If any one agent does not cooperate, the fidelities become state-dependent and are always smaller than the corresponding optimal values. The average fidelities are equal to the balanced value 1/2, which implies that on average the state ineepted by any one of the receivers is a fuUy mixed state. Thus no information leaks out to any dishonest receivers. The security of telecloning and teleflipping have been increased greatly.

Telecloning Quantum States with Trapped Ions

We propose a scheme for telecloning quantum states with trapped ions. The scheme is based on a single ion interacting with a single laser pulse. In the protocol, an ion is firstly measured to determine whether the telecloning succeeds or not, and then another ion is detected to complete the whole procedure. The required experimental techniques are within the scope of what can be obtained in the ion-trap setup.

Scheme to Implement Optimal Symmetric 1→2 Universal Quantum Telecloning Through Cavity-Assisted Interaction

We propose a scheme to implement the optimal symmetric 1 → 2 universal quantum telecloning through cavity-assisted interaction. In our scheme an arbitrary single atomic state can be telecloned to two single atomic states. And three atoms are trapped in three spatially separated cavities respectively. With a particular multiparticle entangled state acting as a quantum information channel and the trapped single atom acting as a quantum network node for its long-lived internal state, quantum information can be telecloned among nodes and can stored in the nodes.

Implementing 1 → M Economical Phase-Covariant Telecloning in Cavity QED

We propose an experimentally feasible scheme to implement the economical 1 → M phase-covariant telecloning based on cavity QED. By the resonant interaction of the atoms with cavity field of a high-Q cavity and the different coupling strength between atoms and cavity field, the scheme can generate quantum entanglement channel in one step. What is more, the operation time and steps do not increase with the increase of atoms.