High-performance cavity-enhanced quantum memory with warm atomic cell
Authors：Lixia Ma, Xing Lei, Jieli Yan, Ruiyang Li, Ting Chai, Zhihui Yan, Xiaojun Jia, Changde Xie and Kunchi Peng
We report a high-performance cavity-enhanced electromagnetically-induced-transparency memory with warm atomic cell in which a scheme of optimizing the spatial and temporal modes based on the time-reversal approach is applied. The memory efficiency up to 67 ± 1% is directly measured and a noise level close to quantum noise limit is simultaneously reached. It has been experimentally demonstrated that the average fidelities for a set of input coherent states with different phases and amplitudes within a Gaussian distribution have exceeded the classical benchmark fidelities.
Quantum interferometer combining squeezing and parametricamplification
Authors：XiaojieZuo, Zhihui Yan, Yanni Feng, Jingxu Ma, Xiaojun Jia, ChangdeXie and Kunchi Peng
We proposeand experimentally demonstrate a compact quantum interferometerinvolving two optical parametric amplifiers and the squeezed statesgenerated within the interferometer are directly used for thephase-sensing quantum state. By both squeezing shot noise andamplifying phase-sensing intensity the sensitivity beyond thestandard quantum limit is deterministically realized and a minimumdetectable phase smaller than that of all present interferometersunder the same phase-sensing intensity is achieved. Thisinterferometric system has significantly potential applications in avariety of measurements for tiny variances of physical quantities.
Deterministic quantum teleportation through fiber channels
Authors：Meiru Huo, Jiliang Qin, Jialin Cheng, Zhihui Yan, Zhongzhong Qin, Xiaolong Su, Xiaojun Jia, Changde Xie, and Kunchi Peng
We experimentally demonstrate deterministic quantum teleportation of an optical coherent state through fiber channels. Two sub-modes of an Einstein-Podolsky-Rosen entangled state are distributed to a sender and a receiver through a 3.0-km fiber, which acts as a quantum resource. The deterministic teleportation of optical modes over a fiber channel of 6.0 km is realized. A fidelity of 0.62 ± 0.03 is achieved for the retrieved quantum state, which breaks through the classical limit of 1/2. Our work provides a feasible scheme to implement deterministic quantum teleportation in communication networks.
Quantum Secret Sharing Among Four Players Using Multipartite Bound Entanglement of an Optical Field
Authors：Yaoyao Zhou, Juan Yu, Zhihui Yan, Xiaojun Jia, Jing Zhang, Changde Xie, and Kunchi Peng
We design and experimentally demonstrate a quantum secret sharing (QSS) protocol, where the dealer modulates a secret on a four-partite bound entanglement (BE) state and then distributes the submodes of the BE state to four spatially separated players. The presented QSS scheme has the capability to protect secrets from eavesdropping and dishonest players, because a nonlocal and deterministic BE state is shared among four authorized players.
Establishing and storing of deterministic quantum entanglement among three distant atomic ensembles
Authors：Zhihui Yan, Liang Wu, Xiaojun Jia, Yanhong Liu, Ruijie Deng, Shujing Li, Hai Wang, Changde Xie, and Kunchi Peng
We present an experimental demonstration on generation, storage, and transfer of deterministic quantum entanglement among three spatially separated atomic ensembles. The off-line prepared multipartite entanglement of optical modes is mapped into three distant atomic ensembles to establish entanglement of atomic spin waves via electromagnetically induced transparency light–matter interaction. Then the stored atomic entanglement is transferred into a tripartite quadrature entangled state of light, which is space-separated and can be dynamically allocated to three quantum channels for conveying quantum information.