An Extended Protocol for Secure Bidirectional Quantum Teleportation and Remote State Preparation in Multi-Qubit Systems

Abstract

This paper proposes a hybrid quantum protocol in which Alice and Bob simultaneously transmit an n-qubit quantum state using a (4n + 1) qubit as a shared quantum channel. This scheme integrates quantum teleportation and remote state preparation (RSP) within a single unified framework, allowing multiple qubits to be transmitted concurrently. The protocol is supervised by a controller named Charlie, which provides an additional security layer during transmission. We demonstrate that the proposed protocol can be generalized to n-qubit, making it suitable for multi-party quantum communication protocols.