Quantum Secure Direct Communication with Quantum Memory

TL;DR

This paper demonstrates the first experimental implementation of quantum secure direct communication (QSDC) integrated with atomic quantum memory, achieving high fidelity and paving the way for practical long-distance quantum networks.

Contribution

It introduces the first experimental demonstration of QSDC combined with quantum memory, enabling effective message control over time in quantum communication.

Findings

Achieved approximately 90% fidelity in entanglement decoding.

Demonstrated the feasibility of QSDC with quantum memory for long-distance communication.

Paved the way for practical quantum networks using QSDC with memory.

Abstract

Quantum communication provides an absolute security advantage, and it has been widely developed over the past 30 years. As an important branch of quantum communication, quantum secure direct communication (QSDC) promotes high security and instantaneousness in communication through directly transmitting messages over a quantum channel. The full implementation of a quantum protocol always requires the ability to control the transfer of a message effectively in the time domain; thus, it is essential to combine QSDC with quantum memory to accomplish the communication task. In this paper, we report the experimental demonstration of QSDC with state-of-the-art atomic quantum memory for the first time in principle. We used the polarization degrees of freedom of photons as the information carrier, and the fidelity of entanglement decoding was verified as approximately 90%. Our work completes a fundamental step toward practical QSDC and demonstrates a potential application for long-distance quantum communication in a quantum network.