Prof. Duan’s group at the Tsinghua University reported a significant advance in the field of quantum information by experimentally realizing entanglement of 25 individually accessible atomic quantum interfaces for the first time. The number of entangled quantum interfaces have increased to by about a factor of six compared with the present record of 4 entangled quantum interfaces reported by the research group at the California Institute of Technology. The work was published on April 20th in Science Advances, entitled “Experimental entanglement of 25 individually accessible atomic quantum interfaces”.
Fig. 1 Experimental setup for generation and verification of multipartite entanglement between a 2D array of atomic quantum interfaces.
A quantum interface links the stationary qubits in a quantum memory with flying photonic qubits in optical transmission channels and constitutes a critical element for the future quantum internet. Entanglement of quantum interfaces is an important step for the realization of quantum networks. In 2001, Prof. Luming Duan and his collaborators proposed a quantum repeater scheme, known as the DLCZ（Duan-Lukin-Cirac-Zoller) scheme, which introduced an efficient type of quantum interface based on the collective enhancement effect in atomic ensembles. The DLCZ scheme is widely followed by the research groups worldwide to realize the entanglement of quantum interfaces, including the famous quantum optics and quantum information group led by Professor Jeff Kimble at Caltech, who realized experimental entanglement of 4 atomic quantum interfaces in 2010, representing the previous state of the art in this direction.
Through heralded detection of photon interference, Prof. Duan’s group generated multipartite entanglement between 25 individually addressable quantum interfaces in a multiplexed atomic quantum memory array and confirmed genuine 22-partite entanglement. This experimental entanglement of a record-high number of individually addressable quantum interfaces makes an important step toward the realization of quantum networks, long-distance quantum communication, and multipartite quantum information processing. The paper was accepted with strong recommendations from the referees: “This is a record-high number and an important milestone for the engineering of the first quantum networks.” by one referee and “The experiment reported here defines the state-of-the-art in the complexity of atomic-photonic interfaces, and I believe this result will have a significant impact in the quantum information science community.” by the other referee.
Fig. 2 Entanglement verification for the 5 × 5 array of atomic ensembles.
This first author of this paper is Yunfei Pu, a PhD candidate at the Tsinghua institute of interdisciplinary information sciences (IIIS) and the corresponding author is Prof. Luming Duan. The other co-authors include the IIIS PhD candidates Nan Jiang, Wei Chang, Chang Li, Sheng Zhang and the PhD candidate Yukai Wu at the University of Michigan. This research was supported with funding from the Ministry of Education, the Ministry of Science and Technology of China, and Tsinghua University.
The paper is available at：http://advances.sciencemag.org/content/4/4/eaar3931.full
(By Yuying Chang)
