2021-11-29

Chinese and foreign scientists realize the optimal detection of high-dimensional quantum entangled states for the first time

By yqqlm yqqlm

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8aa5 facb8b6aa25db6ac318f2f32a7516fbb - Chinese and foreign scientists realize the optimal detection of high-dimensional quantum entangled states for the first time

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

quantum entanglement is the core resource of quantum information process. How to prepare and detect quantum entanglement experimentally is a basic task in the field of quantum information. However, with the increase of system dimension and particle number, the resources consumed by the traditional quantum state tomography, which is a method to detect quantum entangled states, will increase exponentially, so it does not have scalability 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. However, for the common non maximum high-dimensional entangled states, the entanglement witnessing method based on fidelity is not suitable

recently, the research group and theoretical collaborators proposed an optimal quantum entanglement detection method suitable for all two body quantum entangled states. The so-called optimal detection means that in the case of any given state and measurement basis, the method used can give the tightest entangled state boundary and has the strongest ability to distinguish whether the target state is entangled or not. 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 four-dimensional or three-dimensional entangled states that cannot be detected by Fidelity based entanglement witness method, the new method can authenticate their quantum entanglement by using only three groups of measurement bases

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