Bidirectional Quantum Teleportation of GHZ and EPR States Through Entanglement Swapping Utilizing a Pre-established GHZ Channel

In this paper, we present a novel bidirectional quantum teleportation protocol facilitating the simultaneous teleportation of pairs of EPR and GHZ states through entanglement swapping within a six-qubit GHZ channel. This protocol leverages pre-existing GHZ states within the channel, alongside the EPR and GHZ states intended for teleportation, to generate a new entangled state. Subsequently, this state undergoes measurement by Alice and Bob, with the measurement outcomes determining the teleported states. Finally, the successful teleportation of the EPR and GHZ states to each other is ensured through the utilization of CNOT operators, single-qubit and two-qubit measurements, and the application of the identity operator. The proposed protocol presents several advantages over existing protocols, including its bidirectional nature and higher efficiency.