Hefei (ANTARA) – HEFEI, May 30 (Xinhua) — A team of Chinese scientists has set a world record by achieving twin-field quantum key distribution (QKD) over a 1,002-kilometer optical fiber, marking an important step towards quantum networks. large scale in the future.
QKD, a key method in quantum communication, allows two remote users to generate a shared key known only to them, which is used to encrypt and decrypt messages. However, its practical application faces a major obstacle: distance limits, because quantum signals cannot be amplified and the transmission of the line decreases exponentially with distance.
Previously, twin-field QKD had been demonstrated in a laboratory setting over 830 kilometers of rolled fiber.
In a study published in the journal Physical Review Letters, scientists from institutions such as the University of Science and Technology of China, the Jinan Institute of Quantum Technology, and the Shanghai Institute of Microsystems and Information Technology said that the longest achieved distribution distance was 1,002 kilometers at a secure key speed. (secure key rate) reaches 0.0034 bits per second.
During the experiment, the scientists developed a two-frequency (dual-band) phase estimation as well as a superconducting nanowire single-photon detector with very low noise levels to drown out system noise, which hinders the production of secure keys over long distances.
The study has verified the feasibility of twin-field QKD at very long distances, and sheds light on its prospects in long-range quantum communications, according to the China University of Science and Technology.
2023-05-31 05:24:21
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