Optimal detection of high-dimensional quantum entangled states in China University of science and technology
On November 22, academician Guo guangcan team of China University of science and technology made important progress in the research of high-dimensional quantum communication. The research team of Li Chuanfeng and Liu biheng cooperated with Professor Wang Zizhu of University of Electronic Science and technology, Dr. Gao Xiaoqin of Austria and Professor Miguel navascu é s to realize the optimal detection of high-dimensional quantum entangled states for the first time. The relevant results were published in the international well-known journal physics review express.
Quantum entanglement is the core resource of quantum information process. How to prepare and detect quantum entanglement experimentally is the basic task in the field of quantum information. However, with the increase of system dimension and particle number, the resources consumed by quantum state tomography, a traditional method to detect quantum entangled states, will increase exponentially, so it is not scalable in experiments. In order to solve the problem of high-dimensional entanglement detection, the research group has used the entanglement witness method based on fidelity to detect the 32-dimensional two body maximum entangled state, and the fidelity has reached the highest level in the world [Phys. Rev. Lett.125, 090503 (2020)]. However, for the common non maximum high-dimensional entangled states, the entanglement witnessing method based on fidelity is not universal.
To solve this problem, the research group and theoretical collaborators proposed an optimal quantum entanglement detection method, which is suitable for all two body quantum entangled states. In order to test the universality of this method, they skillfully prepared a series of different types of high-dimensional quantum entangled states in experiments, and realized the local measurement of the quantum entangled states, so as to realize the optimal quantum entanglement detection. The experimental results show that for the four-dimensional or three-dimensional entangled states that cannot be detected by the fidelity based entanglement witness method, the new method only needs three groups of measurement bases to verify their quantum entanglement.
This achievement solves the problem of detecting two body high-dimensional entangled states, and lays an important foundation for realizing various high-dimensional quantum information processes and studying the basic problems of quantum physics in high-dimensional systems.
The co first authors of the article are Dr. Hu Xiaomin, a special associate researcher of the Key Laboratory of quantum information, Chinese Academy of Sciences, and Dr. Xing Wenbo, a doctoral student. This study was supported by the Ministry of science and technology, the national foundation of China, the Chinese Academy of Sciences and Anhui Province.
Figure. 1. Experimental results of optimal detection of high-dimensional quantum entangled states. (a) And (b) are two different non maximally entangled states. The entangled states in the green region in the graph can not be detected by the entanglement eyewitness method based on fidelity.
link:
https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.127.220501
