On April 20th, Professor Duan Luming’s research group of the Institute of Cross-Informatics, Tsinghua University, published an article entitled “25 Independently Controlled Quantum Interface Entanglement Experiments” in the Science Advances, a scientific journal. Implemented ('Experimental entanglement of 25 individually accessible atomic quantum interfaces' research paper. This study for the first time achieved quantum entanglement among 25 quantum interfaces, compared to the previous 4 quantum interfaces maintained by the Caltech research group. The world record of entanglement increased by about 6 times the number of interfaces.
Quantum interfaces are used to realize the coherence transformation of quantum information between photons and storage particles (usually atoms), and are important interfaces between quantum memories or quantum computation units and optical quantum communication channels. Similar to the widely used classical interfaces. Quantum interface is a basic component in the field of quantum information. Realizing the entanglement between quantum interfaces is a basic requirement for constructing quantum networks and future quantum networks. In quantum information science, photons have the fastest transmission speed, and they are quantum information. The best carrier, and the atom has a long quantum coherence time, is widely used for the storage of quantum information. The quantum interface connects the photon and the storage atom to realize efficient mutual transformation of quantum information between different carriers.
In 2001, Duan Luming and his collaborators proposed the famous DLCZ (Duan-Lukin-Cirac-Zoller) quantum relay scheme, which proposes to use an atomic ensemble as a quantum interface between the photon and the memory. Benefiting from numerous atomic and optical modes The collective enhancement effect, atomic ensemble-based DLCZ scheme is an ideal choice for quantum interfaces, and has a great influence in the field of quantum information. Many international research groups are devoted to realizing DLCZ-type quantum interfaces and their mutual quantum entanglement. The Institute's famous quantum information and quantum optics expert Kimble's research group had achieved entanglement between four DLCZ-type quantum interfaces in 2010, representing the highest international level ever.
In order to achieve more entanglement between quantum interfaces and to construct a larger quantum entanglement network, Duan Luming's research group has developed a novel two-dimensional quantum interface array that solves related technical problems and can easily achieve entanglement among multiple quantum interfaces. Using beam splitting techniques, the person independently addressed and coherently manipulated the 5×5 quantum interface arrays to create multi-body quantum entanglement states. Between 25 quantum interfaces, the experiment used the entanglement criterion to prove at least 22 with high confidence. The true entanglement above the volume, refreshes the world record of quantum entanglement.
The Reviewer of Science Progress commented highly on this work, saying: 'This is a record number of entanglement and an important milestone in the process of constructing the first quantum network.'
The first author of the thesis is Dr. Yun Yunfei, Ph.D. student of the Institute of Interdisciplinary Information, Tsinghua University, and Corresponding Author is Duan Luming. Other authors include Jiang Nan, Chang Wei, Li Chang, Zhang Sheng, PhD students of the Institute of Interdisciplinary Information, and Wu Yuxi, a doctoral student at the University of Michigan, USA. The project received financial support from the Ministry of Education, the Ministry of Science and Technology and Tsinghua University.