A controlled quantum teleportation scheme of an N-particle unknown state via three-particle W1 states

In this paper a controlled quantum teleportation scheme of an N-particle unknown state is proposed when N groups of three-particle W1 states are utilized as quantum channels. The quantum information of N-particle unknown state is transmitted from the sender to the recipient under the control of all supervisors. It can be realized with a certain probability. After the sender makes Bell-state measurements and the supervisors perform the computational basis measurements, the recipient will introduce auxiliary particles and carry out unitary transformations depending on classical information from the sender and the supervisors. Finally, the computational basis measurement will be performed by the recipient to confirm whether the teleportation succeeds or not. The successful completion of the scheme relies on all supervisors＇ cooperation. In addition, the fidelity and security of the scheme are discussed.

Experimental realization of quantum controlled teleportation of arbitrary two-qubit state via a five-qubit entangled state

Quantum controlled teleportation is the transmission of the quantum state under the supervision of a third party.This paper presents the theoretical and experimental results of an arbitrary two-qubit quantum controlled teleportation scheme,in which the sender Alice only needs to perform two Bell state measurements and the receiver Bob can perform an appropriate unitary operation to reconstruct the arbitrary two-qubit states under the control of the supervisor Charlie.The operation process of the scheme is verified on the IBM quantum experience platform,and the accuracy of the transmitted quantum state is further checked by performing quantum state tomography.Meanwhile,a good fidelity is obtained by using the theoretical density matrix and the experimental density matrix.A sequence of photonic states is introduced to analyze the possible intercept-replace-resend,intercept-measure-resend,and entanglement-measure-resend attacks on this scheme.The results proved that our scheme is highly secure.

Perfect quantum controlled teleportation via a novel threeparticle partially entangled channel

Recently Li et al. proposed special partially entangled states serving as quantum channel in quantum controlled teleportation, while there are some limitations in their scheme. Based on that, we present a possible improvement in this paper. We construct a novel three-particle partially entangled state which is suitable for perfect controlled teleportation. A simple quantum circuit is designed to obtain this state. We evaluate quantum controlled teleportation from three points of view： teleportation fidelity, success probability and the controller＇s power. Detailed calculations and simulation analyses show that the constructed state is a suitable channel for controlled teleportation of arbitrary qubits, unit teleportation fidelity and 100% success probability can be achieved. Meanwhile, as long as channel＇s entanglement degree equals to or greater than 3/4, the controller＇s power can be guaranteed.