Four-directional quantum controlled teleportation using a single quantum resource

In this paper, a quantum teleportation protocol has been proposed that can simultaneously transmit quantum states in four directions using a single entangled channel. This means that there are four senders who want to transmit state information, and they are Alice, Bob, Charlie, and David. In order to ensure the security of information transmission, the information state of the four is transmitted to four receivers Fancy1, Fancy2, Fancy3, and Fancy4 under the control of the controller Elle. Through unitary transformation and entanglement property, receivers can recover the original quantum state from the four senders, which is easy to implement. The teleportation protocol is perfect.

Semi-quantum secret sharing protocol using W-state

Quantum secret sharing protocol, which lets a master share a secret with his/her agents and the agents can recover the master’s secret when they collaborate, is an important research issue in the quantum information field. In order to make the quantum protocol more practical, the concept of semi-quantum protocol is advanced by Boyer et al. Based on this concept, many semi-quantum secret sharing protocols have been proposed. The various entanglement states (including Bell state, GHZ state and so on) were used to be the quantum resources in these SQSS protocols, except for W-state which is the other multi-qubit entanglement state and different from GHZ states. Therefore, this study wants to use the entanglement property of W-state to propose the first three-party SQSS protocol and analyze the proposed protocol is free from the well-known attacks.

MAXIMAL ENTANGLED FOUR-QUBIT STATE AND ITS PREPARATION IN CAVITY QED SYSTEM

In this paper, we explore the entanglement property of the nine families of four-qubit states and prove what are the maximally entangled four-qubit states. Then, we introduce a simple scheme to prepare this kind of states in cavity QED system.

MULTIPLE CONCURRENCE OF MULTI-PARTITE QUANTUM SYSTEM

We propose a new way of description of the global entanglement property of a multi-partite pure state quantum system. Based on the idea of bipartite concurrence, by dividing the multi-partite quantum system into two subsystems, a combination of all the bipartite concurrences of a multi-partite quantum system is used to describe the entanglement property of the multi-partite system. We derive the analytical results for GHZ-state, W-state with arbitrary number of qubits, and cluster state with the number of particles no greater than 6.

ENTANGLEMENT PROPERTY AND MONOGAMY RELATION OF GENERALIZED MIXED W STATES

We introduce a new class of multipartite entangled mixed states with pure state decompositions of generalized W states, similar to Schmidt-correlated states having generalized GHZ states in the pure state decomposition. The entanglement and separability properties are studied according to PPT operations. Monogamy relations linked to these states are also investigated.

CONTROLLED AND REMOTE IMPLEMENTATION OF A SPLIT QUANTUM ROTATION AND SENDER-ENCODED SECRET SHARING

A quantum rotation can be divided into M pieces and teleported from a sender onto M distant receivers via the control of N agents in a quantum network. We utilize the entanglement property of a (2M + N + 1)-qubit Einstein–Podolsky–Rosen (EPR) — Greenberger–Horne–Zeilinger (GHZ) state to design a theoretical scheme for implementing these rotations remotely with unit fidelity and unit probability. The feature of the scheme is that, apart from a sender and M receivers, N agents are included in the process as controllers. Should any one of the N agents not cooperate, the receivers could not gain the original rotations. This scheme can be used to sender-encoded quantum secret sharing. It definitely has the strong security.