Quantum communication created by Chinese scientists can be directly and safely transmitted at 500 meters

The quantum secure direct communication created by Chinese scientists has once again taken a big step forward in the process of practical application.

It was reported from the joint experimental group of Tsinghua University and Nanjing University of Posts and Telecommunications on November 14 that after announcing in June this year that the theoretical scheme of quantum secure direct communication was verified through quantum storage in the laboratory, they used a 500-meter optical fiber for the first time in recent days. The entangled quantum phenomenon realizes the direct and secure transmission of quantum information. And theoretical analysis proves that under the current test conditions, it is possible to achieve quantum secure direct communication for dozens of kilometers.

Quantum Communication refers to a new type of communication method that uses quantum entanglement effects for information transmission. Quantum communication is a new cross-discipline developed in the past two decades, and a new research field combining quantum theory and information theory.

Quantum communication mainly involves: quantum cryptographic communication, quantum teleportation and quantum dense coding, etc. This discipline has gradually moved from theory to experiment, and is developing towards practicality. Efficient and safe information transmission has attracted increasing attention. Based on the basic principles of quantum mechanics, quantum communication has the characteristics of high efficiency and absolute security, and has therefore become a research hotspot in quantum physics and information science in the world.

Current experiments show that optical fiber-based quantum secure direct communication can achieve a transmission rate close to the current commercial quantum key distribution. Quantum secure direct communication is to be fully commercialized. Although there are still many improvements, this experiment is a crucial step for quantum secure direct communication to be practical.