Designing Filter Functions of Frequency-Modulated Pulses for High-Fidelity Two-Qubit Gates in Ion Chains
Designing Filter Functions of Frequency-Modulated Pulses for High-Fidelity Two-Qubit Gates in Ion Chains
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DOI：
10.1103/physrevapplied.19.014014
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发表时间：
2022-06
影响因子：
4.6
通讯作者：
Mingyu Kang;Ye Wang;Chao Fang;Bichen Zhang;O. Khosravani;Jungsang Kim;K. Brown
中科院分区：
文献类型：
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作者：
Mingyu Kang;Ye Wang;Chao Fang;Bichen Zhang;O. Khosravani;Jungsang Kim;K. Brown
量子计算机中的高保真双量子比特门经常受到波动的实验参数的阻碍。时变参数波动的影响导致量子比特上的相干噪声，这可以通过设计具有适当滤波函数的控制信号来抑制。在这里，我们开发了用于捕获离子量子计算机的M{\o}lmer-S{\o}rensen门的滤波器函数，该函数可以准确预测由于任何频率下的小参数波动而导致的门误差的变化。然后，我们设计的频率调制的激光脉冲的滤波器功能，并比较这种方法与脉冲是强大的静态偏移的运动模式频率。在实验上，我们测量了运动模的噪声谱，并将其用于设计滤波器函数，在五离子链中将门保真度从99.23（7）%提高到99.55（7）%。
High-fidelity two-qubit gates in quantum computers are often hampered by fluctuating experimental parameters. The effects of time-varying parameter fluctuations lead to coherent noise on the qubits, which can be suppressed by designing control signals with appropriate filter functions. Here, we develop filter functions for M{\o}lmer-S{\o}rensen gates of trapped-ion quantum computers that accurately predict the change in gate error due to small parameter fluctuations at any frequency. We then design the filter functions of frequency-modulated laser pulses, and compare this method with pulses that are robust to static offsets of the motional-mode frequencies. Experimentally, we measure the noise spectrum of the motional modes and use it for designing the filter functions, which improves the gate fidelity from 99.23(7)% to 99.55(7)% in a five-ion chain.