Researchers at Shanghai Jiao Tong University have achieved a significant milestone in quantum technology by establishing a quantum secure direct communication (QSDC) network. This groundbreaking network spans approximately 300 kilometers, making it practical for inter-city communications.

According to a report by Science and Technology Daily, the innovative team successfully maintains over 85 percent quantum state fidelity during transmission between pairs of users connected through the network.

The details of this remarkable research were published in the journal Science Bulletin, highlighting key advancements that address traditional limitations associated with quantum networks, specifically regarding transmission distance and user capacity.

The researchers have engineered a double-pumped, expandable QSDC network that performs effectively even in noisy environments. The system has demonstrated a stable photon pair rate of between 300 to 400 Hz, which theoretically supports communication speeds of several bits per second.

This achievement follows a previous record set by a team in Beijing in February, where they successfully demonstrated quantum direct communication over a distance of 104.8 kilometers using standard optical fiber.

Quantum direct communication, initially proposed by researchers at Tsinghua University, guarantees secure communication through the application of quantum states. It encompasses features such as eavesdropping detection and prevention, compatibility with existing networks, and streamlined management processes.

The newly developed QSDC systems are expected to find widespread applications in sectors with rigorous information security needs, particularly in finance, where the integrity and confidentiality of data are paramount.

In addition to QSDC, this technique is a vital complement to quantum key distribution (QKD), which collectively lays the groundwork for the potential future of a global quantum internet.

In a significant accomplishment, an international team led by Chinese scientists has also successfully demonstrated real-time QKD communication over a staggering distance of more than 12,900 kilometers between China and South Africa, showcasing the capabilities of quantum technology on a global scale.