Professor Han Zhengfu of the academician team of Guo Guangcan of the University of Science and Technology of China and his collaborators Wang Shuang, Yin Zhenqiang, Chen Wei, etc., proposed a new semi-device-independent quantum random number generator protocol and carried out experimental verification. The protocol eliminates the need to characterize the probing device even when the light source is not trusted, and safe quantum random numbers can be quickly generated using everyday light sources. This protocol comprehensively improves the safety and practicability of quantum random number generators, and lays a solid foundation for the practical application of semi-device-independent quantum random number generators. The relevant research results have been published online in the well-known international academic journal “Physical Review Letters”.
Schematic diagram of the structure of the new semi-device-independent quantum random number generator courtesy of the University of Science and Technology of China
Random numbers are an important basic resource in the information age. The quantum random number generator generates true random numbers with inherent randomness based on the principles of quantum physics, which provides great assistance for scientific simulation, cryptography and other fields. In the current widely concerned quantum secure communication, the quantum random number generator is a key link. However, the non-ideality that a quantum random number generator in reality may have can disrupt the unpredictability and privacy of random numbers. Although the fully device-independent quantum random number generator can tolerate these non-idealities, its protocol implementation is difficult, the random number generation rate is low, the cost is high, and it is still far from practical application.
Semi-device-independent quantum random number generators have received a lot of attention because of the great relaxation of requirements for some components, providing a practical and feasible implementation of safety. However, because the existing semi-device-independent solution ignores the impact of some key factors on its performance, it limits its application in real-world conditions.
In response to this problem, Han Zhengfu’s research group conducted in-depth research, proposed a source-independent protocol that tolerates the probe’s post-pulse in 2020, and further reduced the sensitivity of source-independent quantum random number generators to non-ideal factors in 2022. These efforts significantly improve the usefulness of source-independent quantum random number generators, but they all still require accurate characterization of the measurement device.
Recently, based on the uncertain relationship of smooth entropy and the quantum residual hash theorem, the research group proposes a new semi-device-independent quantum random number generator protocol that does not require the characterization of the measurement device, and proves the safety of the protocol under the condition that the source is not trusted and the probe end is not characterized.
The research team completed the verification experiment using both the daily light source and the laser of the halogen lamp, and the random number rate generated was comparable to that of the current commercial random number generator, but the safety was significantly better than the latter.
While ensuring the rapid generation of random numbers and the simplicity and practicality of the system, this achievement greatly reduces the requirements for device credibility and characterization, and its ideas and implementation schemes have an important role in promoting the breakthrough of the research bottleneck of high-performance and high-safety quantum random number generators. (Source: China Science Daily Wang Min)
Related paper information:https://doi.org/10.1103/PhysRevLett.129.050506