China Science and Technology University realizes measurement-independent high-dimensional quantum guidance for the first time

[ Instrument Network Instrument Development ] Guo Guangcan, a member of the Chinese Academy of Sciences and a professor at the University of Science and Technology of China, made new progress in the study of basic problems in quantum mechanics. The laboratory Li Lifeng, Liu Biheng and others collaborated with Australian theoretical physicists to observe the first experimental observation. Device-independent high-dimensional quantum guidance and use it to generate private quantum random numbers. The research results were published on the International Physics Journal "Physical Review Letter" on October 23.

Quantum guidance is a type of quantum nonlocality between quantum entanglement and Bell nonlocality. It describes that local measurements on one particle in an entangled particle pair can affect another particle non-locally. The ability of the state. Quantum guidance has important applications in quantum information tasks such as quantum key distribution, quantum channel identification, and random number generation. This can lead to loopholes in quantum-guided experiments due to the limited performance of experimental equipment or the possibility of being manipulated by hostiles. Taking the quantum guidance of entangled photon pairs as an example, since the efficiency of a single photon detector is limited, undetected photons can in principle be utilized by potential adversaries, which makes the results of quantum pilot experiments unreliable. In order to solve this problem, theoretical physicists have designed a quantum refereed quantum-guided identification method. By introducing third-party arbitration, the quantum-guided experimental test becomes independent of the measurement equipment.

Inspired by this, Li Chuanfeng, Liu Biheng and others skillfully constructed a high-dimensional quantum-guided witness operator with no measurement equipment. The first experiment realized high-dimensional quantum guidance independent of measurement equipment. The research team used a parametric down-conversion process to prepare a series of high-fidelity three-dimensional entangled states on polarization and path degrees of freedom. Then the arbitrator sends a series of test requirements to the entangled parties, collecting the two-dimensional data test high-dimensional quantum guidance inequality, the test results up to 1.983 (0.002), far exceeding the classical theoretical limit of 1.37 in the three-dimensional case, confirming that these entangled states have quantum guidance characteristic. As an application, the research team further applied experimentally observed data to the generation of random numbers. Each entangled photon pair yielded a 1.106 (0.023) bit of private quantum random number, exceeding the theoretical limit achievable with two-dimensional entangled states (1 bit). Each entangled photon pair) fully demonstrates the advantages of high-dimensional entanglement in the process of quantum information.

This work is the first experimental attempt based on the high-dimensional system to measure the device-independent quantum information task, which will play an important role in the research of the basic problems of quantum physics and the measurement of device-independent quantum information processes.

The first author of the article is Guo Wei, a doctoral student at the Key Laboratory of Quantum Information of the Chinese Academy of Sciences. The research was supported by the Ministry of Science and Technology, the National Fund Committee, the Chinese Academy of Sciences, and Anhui Province.