Quantum Secure Direct Communication Against Collective Noise Based on W States

Abstract

The three-particle W state is used as a quantum resource in this research. The sender’s unitary operator works on the Bell state via the Pauli and controlled Z gates and encodes the unitary operations. Subsequently, the receiver measures the joint Bell state. Next, the receiver identifies the sender’s unitary process and decodes the secret message for its retrieval. Finally, two quantum secure direct communication protocols are developed under collective noise channels. These protocols use different logical Bell states to resolve two different types of noise in the transmission channel. The protocol compensates for the weaknesses of three-particle W state quantum secure direct communication in resisting the collective noise. Moreover, the logical W state is applied to protect the quantum state, which increases its fidelity and improves the information transmission rate. In addition, the security of this study’s protocols is demonstrated using a rigorous security analysis of diverse attacks.