A faithful solid-state spin-wave quantum memory for polarization qubits  

可存储偏振量子比特的高保真固态自旋波量子存储器

作　　者：Ming Jin You-Zhi Ma Zong-Quan Zhou Chuan-Feng Li Guang-Can Guo 靳明;马有志;周宗权;李传锋;郭光灿(CAS Key Laboratory of Quantum Information,University of Science and Technology of China,Hefei 230026,China;CAS Center for Excellence in Quantum Information and Quantum Physics,University of Science and Technology of China,Hefei 230026,China)

机构地区：[1]CAS Key Laboratory of Quantum Information,University of Science and Technology of China,Hefei 230026,China [2]CAS Center for Excellence in Quantum Information and Quantum Physics,University of Science and Technology of China,Hefei 230026,China

出　　处：《Science Bulletin》2022年第7期676-678,共3页科学通报（英文版）

基　　金：supported by the National Key R&D Program of China (2017YFA0304100);the National Natural Science Foundation of China (11774331, 11774335, 11821404, and 11654002);the Fundamental Research Funds for the Central Universities (WK2470000026 and WK2470000029);support from the Youth Innovation Promotion Association CAS

摘　　要：Memory-based quantum communication can overcome the distance limit by adopting either the approach of a quantum repeater[1]or a transportable quantum memory[2,3].Photonic quantum memories have been demonstrated with various physical systems,including single atoms inside optical cavities[4],atomic gases[5]and impurities in solids[6].As an emerging solid-state platform,rare-earth-ion doped solids have enabled optical quantum storage with remarkable performances[6–9].Moreover,the rare-earth-ion doped crystal,i.e.,Eu^(3+):Y_(2)SiO_(5),is currently the only candidate for a transportable photonic quantum memory,due to its hours-long optical storage times[3].Despite these remarkable achievements,rare-earth-ion doped crystals typically have birefringence and anisotropic absorption which make the storage of polarization-qubits become a great challenge.偏振编码的量子比特具有单模式传输、操作精度高和抗干扰能力强的特点,在量子信息任务中获得了广泛的应用.对偏振量子比特的高保真存储,是构建大尺度量子网络的基本需求.固体材料的光吸收一般是各向异性的,所以已有的偏振固态量子存储器需要两块晶体或两次通过单块晶体,导致装置复杂且可靠性不高.本研究利用Y_(2)SiO_(5)晶体中第二类替位^(151)Eu^(3+)的均匀吸收特性,结合高信噪比的无噪声光子回波量子存储方案,最终基于单次通过的单块晶体即可实现对偏振量子比特的高保真量子存储.使用单光子级的弱相干脉冲作为入射,实测的量子存储过程保真度达到了0.919(24),显著超出了使用经典的测量和制备策略可以获得的保真度上限.这种紧凑的存储器件为实现量子U盘和基于量子存储的量子网络提供了有利的解决方案.

关 键 词：量子比特 量子存储 存储器件 保真度 量子网络 光子回波 U盘 高保真 

分 类 号：TP333[自动化与计算机技术—计算机系统结构] O413[自动化与计算机技术—计算机科学与技术]