Controlled Bidirectional Quantum Teleportation of Arbitrary Single Qubit via a Non-maximally Entangled State

Because of the decoherence induced by surrounding environments, the maximally entangled state is usually difficult to prepare and maintain. In this study, a teleportation scheme was developed using a five-qubit non-maximally entangled state as the quantum channel. With Charlie's permission, Alice and Bob could teleport a single-qubit state to each other deterministically. The scheme was introduced in a noiseless environment first. As we all know, when a non-maximally entangled state was used as the quantum channel, teleportation might fail, and the state to be transmitted would be destroyed. To solve this problem, in this scheme, an appropriate unitary tranasformation was performed on the non-maximally entangled state in advance with the help of an auxiliary qubit. Then, we analyzed the influence of the quantum noise on the fidelity of the desired state using the example of amplitude damping during the qubit distribution. Finally, we utilized the weak measurement and the corresponding reversing measurement to increase fidelity. The results showed that the weak measurement was an effective method for enhancing teleportation.