强驱动单态-三重态量子比特的高保真单比特门  

High-fidelity single-qubit gates of a strong driven singlet-triplet qubit

作　　者：刘启沛 张程贤 薛正远[1,3,4] Liu Qi-Pei;Zhang Cheng-Xian;Xue Zheng-Yuan(Key Laboratory of Atomic and Subatomic Structure and Quantum Control(Ministry of Education),School of Physics,South China Normal University,Guangzhou 510006,China;School of Physical Science and Technology,Guangxi University,Nanning 530004,China;Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials,Guangdong-Hong Kong Joint Laboratory of Quantum Matter,Frontier Research Institute for Physics,South China Normal University,Guangzhou 510006,China;Hefei National Laboratory,Hefei 230088,China)

机构地区：[1]华南师范大学物理学院,原子亚原子结构与量子调控教育部重点实验室,广州510006 [2]广西大学物理科学与工程技术学院,南宁530004 [3]华南师范大学物理前沿科学研究院,广东省量子调控与量子材料重点实验室,粤港量子物质实验室,广州510006 [4]合肥国家实验室,合肥230088

出　　处：《物理学报》2023年第20期195-201,共7页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:11905065,12275090);广西科技基地和人才专项(批准号:桂科AD22035186);广东省重点实验室(批准号:2020B1212060066);科技创新2030——“量子通信与量子计算机”重大项目(批准号:2021ZD0302303)资助的课题。

摘　　要：半导体量子点量子比特是最有希望实现量子计算的候选者之一.其中自旋单态-三重态量子比特因具有全电控制和读取准确的优良性质而备受关注.为增强对电荷噪声的免疫,通常引进强脉冲驱动以尽可能加快门操作速度.但是,强驱动脉冲引起的复杂动力学导致旋波近似不再适用,反而会阻碍高保真度比特操作的实现.本文提出了一种增加简单的正交脉冲的方法,可以很好地抑制强驱动引起的高频振荡项的操作错误.数值计算结果表明,NOT门的保真度在无噪声时可达99.99%且操作时间只需2 ns.特别地,即便电荷噪声强度到了2μe V的水平,NOT门的平均保真度也可高于99.9%.值得注意的是,该方案同时也适用于任意单比特量子门的优化.因此,本文的脉冲优化方案将有助于获得快速高保真度的自旋单态-三重态量子比特.2eV Semiconductor quantum dot qubits are one of the most promising candidates for quantum computing.Among them,singlet-triplet qubits have attracted much attention due to their excellent properties of all-electric control and accurate readout.To improve qubit immunity to charge noise,strong driving pulses are usually introduced to make operation as fast as possible.However,the complex dynamics induced by strong driving pulses make the rotating wave approximation inapplicable and hinder the implementation of high-fidelity qubit operation.In this work,we present a method of utilizing simple quadrature pulses to correct errors of highfrequency oscillatory terms induced by strong driving.A scheme to obtain these pulses is proposed based on a full quantization of the system and derivative removal by adiabatic gate(DRAG)theory,as the former clarifies the elementary processes of strong driving effects and enables the latter to find correction pulse shapes.The numerical simulation results show that,a NOT gate with 99.99%fidelity and gate time as short as 2 ns can be achieved with the help of the control pulses of this method,which indicates that the control error brought by strong driving is no longer a limiting factor.In particular,NOT gate fidelity higher than 99.9%is achievable even when the charge noise is at a level of 2μe V.Notice that this method can be applied to any resonantdriving single-qubit rotation but not just NOT gates.Therefore,our approach will facilitate qubits to realize fast,high-fidelity single-qubit gates under charge noise.

关 键 词：单态-三重态量子比特 量子单比特门 强驱动 

分 类 号：O413[理学—理论物理]