超导量子电路材料  

Materials in superconducting quantum circuits

作　　者：熊康林 冯加贵[1,2] 郑亚锐 崔江煜 翁文康 张胜誉 李顺峰 杨辉 Kanglin Xiong;Jiagui Feng;Yarui Zheng;Jiangyu Cui;Manhong Yung;Shengyu Zhang;Shunfeng Li;Hui Yang(Gusu Laboratory of Materials,Suzhou 215123,China;Suzhou Institute of Nano-Tech and Nano-Bionics,Chinese Academy of Sciences,Suzhou 215123,China;Tencent Quantum Laboratory,Shenzhen 518000,China;Huawei Central Research Institute,Shenzhen 518129,China)

机构地区：[1]材料科学姑苏实验室,苏州215123 [2]中国科学院苏州纳米技术与纳米仿生研究所,苏州215123 [3]腾讯量子实验室,深圳518000 [4]华为技术有限公司中央研究院,深圳518129

出　　处：《科学通报》2022年第2期143-162,共20页Chinese Science Bulletin

基　　金：江苏省自然科学基金(BK20180255);中国科学院青年创新促进会项目(2019319);中国科学院苏州纳米技术与纳米仿生研究所自有项目(Y9AAD110)资助。

摘　　要：超导量子电路由超导的电容、电感、约瑟夫森结、传输线构成,在超低温下表现出宏观量子效应.由于超导体自身的耗散极低,超导量子电路的一个重要应用研究方向是具有长相干时间的超导量子比特.超导量子电路沿用了传统集成电路的微纳米制造工艺,包含多个超导量子比特的芯片也能进行规模化加工和封装.但是,在超导量子电路的结构设计、材料制备、芯片制造、工作环境等各个环节都会引入耗散通道,限制了超导量子比特的相干性.从微观机理上分析,这其中大部分通道都与量子电路材料及表界面相关,因此从材料和工艺出发,全方位探索高质量超导量子电路的制备是进一步推进其应用的必然趋势.Superconducting quantum circuits(SQCs), composed of superconducting capacitors, inductances, Josephson junctions,and transmission lines, exhibit macroscopic quantum effects at ultra-low temperatures. Due to the extremely low dissipation of superconductors, an important application of SQCs is superconducting qubits with long coherence time.Quantum computing based on superconducting qubits is a leading physical realization method of quantum computing,which is theoretically capable of accelerating many computational problems including quantum simulation, database searching, and optimization. In the long run, to use the power of quantum computing to its full extent, universal quantum computers should be constructed with quantum error correction. In the short term, one of the most pressing targets of the superconducting quantum computing community is to demonstrate quantum advantage using noisy intermediate-scale quantum chips. Both goals rely on the increasing of the number of coupled qubits in a quantum circuit and the quality of these qubits, which dictate the breadth and the depth of a problem it can solve, respectively. The fabrication of SQCs has adopted a few manufacturing processes from conventional integrated circuits. Quantum chips containing multiple superconducting qubits can be made and packaged on a large scale. “Quantum supremacy” has been demonstrated on a quantum chip with fifty-three qubits fabricated using the flip-chip bonding technology. However, to demonstrate quantum advantage, the quality and quantity of qubits need to increase simultaneously. Dissipative channels emerge in circuit design, material preparation, chip fabrication, and working environment, limiting the lifetime of superconducting qubits.For quantum chips with tens to hundreds of qubits, the integration will also introduce extra processing steps which may degrade the qubits, and unwanted coupling to loss channels. Most of these channels are microscopically related to materials constructing the quantum chips, chip surfaces, and

关 键 词：超导量子比特 退相干 二能级系统 准粒子 约瑟夫森结 

分 类 号：O413[理学—理论物理] O511[理学—物理]