发表机构
Tohoku University; RIKEN Center for Quantum Computing; The University of Tokyo; Inamori Research Institute for Science (InaRIS); National Institute of Information and Communications Technology (NICT)（东北大学; 理化学研究所量子计算中心; 东京大学; 稻盛科学研究所; 信息通信研究机构）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究利用外延NbN/AlN/NbN约瑟夫森结实现自分流超导磁通量子比特，获得797 MHz高非谐性和13-25微秒寿命，显著减小器件尺寸，为大规模超导量子计算提供新方案。
AI 中文摘要
我们报告了一种自分流超导磁通量子比特（SSFQ）的演示，该量子比特通过使用完全外延生长的NbN/AlN/NbN约瑟夫森结，实现了超紧凑、强非谐性和长寿命。基于NbN结的SSFQ实现了797 MHz的高非谐性，并且与具有大分流电容的电容分流（C-shunt）磁通量子比特相比，量子比特的占地面积大幅减少。SSFQ的寿命达到13-25微秒，这与基于NbN的C-shunt磁通量子比特和基于Al的磁通量子比特（其结尺寸小10倍以上）相当或相对更高。这表明，大型外延NbN基结可以用于SSFQ以及具有相对较大结的合并元件transmon。本工作呈现的结果将为可扩展量子比特提供新的选择，以及为实现大规模超导量子计算机的材料平台。
英文摘要
We report a demonstration of a self-shunted superconducting flux qubit (SSFQ) as an ultracompact, strongly anharmonic, and long-lifetime qubit by using the full epitaxially grown NbN/AlN/NbN Josephson junctions. The NbN-junction-based SSFQ achieved a high anharmonicity of 797 MHz as well as drastically reduced footprint of the qubit compared to capacitively shunted (C-shunt) flux qubits with a large shunt capacitor. The lifetime of the SSFQ reached 13 - 25 $μ$s, which is comparable to or relatively higher than that of NbN-based C-shunt flux qubits and Al-based flux qubits with more than 10 times smaller junctions. This indicates that the large epitaxial NbN-based junction can be adopted for SSFQ as well as merged-element transmon with the relatively large junctions. The results presented in this work will offer a new choice of the scalable qubits as well as the material platform toward the realization of large-scale superconducting quantum computers.
Comments14 pages, 6 figures
