Recently, "Physical Review Letter" published a new world record created by Chinese scientists in the field of quantum communication. Pan Jianwei and his colleagues Zhang Qiang and Chen Tengyun of the University of Science and Technology of China, and Wang Xiangbin of Tsinghua University, Shanghai Institute of Microsystems, Chinese Academy of Sciences, Jinan Institute of Quantum Technology, etc. researchers cooperation, for the first time more than 400 kilometers of quantum measurement equipment against hacker attacks regardless of quantum key distribution in the international arena, which greatly promoted the development of both safe and practical long-distance quantum optical fiber communication.
Quantum key distribution provides an unconditionally secure shared key for users who are separated. Since the first quantum key distribution protocol (BB84 protocol) was proposed in 1984, increasing the secure communication distance, improving the security rate and improving the security of the real system are the three most important goals for the development of practical quantum key distribution.
In recent years, Pan Jianwei Group of China University of Science and Technology has carried out invasive experimental research around the above three objectives and achieved a series of international leading results: In 2013, the first time in the world to achieve measurement equipment-independent quantum key distribution, completely solved All hacking attacks on detection systems were selected by the American Physical Society as a major international physics advancement in 2013; in 2014, the measurement of device-independent quantum key distribution secure communication distances extended to 200 kilometers, creating a new world record; 2016 In the year, the quantum key distribution network based on non-trusted relay was realized for the first time in the world. However, the safety code rate of these experiments is low, which severely limits the practical application of the technology.
In response to this problem, Wang Xiangbin of Tsinghua University proposed a four-strength optimization theory method, which can greatly improve the safety code rate and safety distance. Theoretical analysis shows that the proposed method can increase the code rate by nearly two orders of magnitude under typical experimental conditions, thus greatly improving the practical level.
In 2016, Pan Jianwei further developed the stable two-photon interference technology and long-term stability technology of the system, using the theoretical method developed by Professor Wang Xiangbin, combined with the high-efficiency low-noise superconducting nanowire single photon detection developed by the researcher of Shanghai Microsystems. The device successfully expands the measurement-device-independent quantum key distribution security transmission record to 404 km ultra-low loss fiber and 311 km of common fiber distance, creating a new world record for fiber transmission distance.
It is particularly worth noting that under the same realistic conditions, even with a perfect single photon source, the BB84 protocol cannot be implemented at such a long transmission distance. The safety code rate of the experiment at 207 km is more than 500 times higher than the 200 km test in 2014; the security code rate of 102 km is enough to ensure a secure voice call, thus fully verifying the measurement device independent quantum density. The usefulness of key distribution.
The result was recently published in the "Physical Review Letter", an authoritative journal of international physics. The reviewer highly praised it as "an outstanding achievement" and "broken the ultimate limit of transmission of single photon sources under the BB84 protocol."
The 0-10V dimmable series of Constant Voltage Class 2 LED Drivers from ZHPOWER offers both UL 8750 Listed and CLASS 2 rated. With universal input voltage ranging from 120VAC, the series of 12V/24V DC led drivers are designed for commercial, industrial and residential applications. Our 0-10V dimming delivers smooth flicker-free linear dimming down to 1% with most LED`s and a wide variety of compatible dimmers.
Dimmable Led Driver,Ul Class 2 Dimmable Driver,Dimmable Led Driver 48W,Led Driver Dimmer 80W
Shenzhenshi Zhenhuan Electronic Co Ltd , https://www.szzhpower.com