Threshold-independent method for single-shot readout of spin qubits in semiconductor quantum dots  

作　　者：胡睿梓 祝圣凯 张鑫 周圆 倪铭 马荣龙 罗刚 孔真真 王桂磊 曹刚 李海欧 郭国平 Rui-Zi Hu;Sheng-Kai Zhu;Xin Zhang;Yuan Zhou;Ming Ni;Rong-Long Ma;Gang Luo;Zhen-Zhen Kong;Gui-Lei Wang;Gang Cao;Hai-Ou Li;Guo-Ping Guo(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;Key Laboratory of Microelectronics Devices and Integrated Technology,Institute of Microelectronics,Chinese Academy of Sciences,Beijing 100029,China;Beijing Superstring Academy of Memory Technology,Beijing 100176,China;Origin Quantum Computing Company Limited,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 [3]Key Laboratory of Microelectronics Devices and Integrated Technology,Institute of Microelectronics,Chinese Academy of Sciences,Beijing 100029,China [4]Beijing Superstring Academy of Memory Technology,Beijing 100176,China [5]Origin Quantum Computing Company Limited,Hefei 230026,China

出　　处：《Chinese Physics B》2024年第1期274-279,共6页中国物理B（英文版）

基　　金：Project supported by the National Natural Science Foundation of China (Grant Nos.12074368,92165207,12034018,and 62004185);the Anhui Province Natural Science Foundation (Grant No.2108085J03);the USTC Tang Scholarship。

摘　　要：The single-shot readout data process is essential for the realization of high-fidelity qubits and fault-tolerant quantum algorithms in semiconductor quantum dots. However, the fidelity and visibility of the readout process are sensitive to the choice of the thresholds and limited by the experimental hardware. By demonstrating the linear dependence between the measured spin state probabilities and readout visibilities along with dark counts, we describe an alternative threshold-independent method for the single-shot readout of spin qubits in semiconductor quantum dots. We can obtain the extrapolated spin state probabilities of the prepared probabilities of the excited spin state through the threshold-independent method. We then analyze the corresponding errors of the method, finding that errors of the extrapolated probabilities cannot be neglected with no constraints on the readout time and threshold voltage. Therefore, by limiting the readout time and threshold voltage, we ensure the accuracy of the extrapolated probability. We then prove that the efficiency and robustness of this method are 60 times larger than those of the most commonly used method. Moreover, we discuss the influence of the electron temperature on the effective area with a fixed external magnetic field and provide a preliminary demonstration for a single-shot readout of up to 0.7K/1.5T in the future.

关 键 词：quantum computation quantum dot quantum state readout 

分 类 号：O471.1[理学—半导体物理]