论文标题
使用脉冲动力解耦的稳健的两倍大门
Robust Two-Qubit Gates Using Pulsed Dynamical Decoupling
论文作者
论文摘要
我们使用射频（RF）受控的捕获量量子处理器介绍了两数Qubit相位门的实验实现。 RF驱动的栅极是通过仅应用于离子载体跃迁的脉冲动力学去耦序列生成的。它允许具有高保真结果的可调相移，特别是在Ramsey-type测量中观察到了最高$ 99 _ { - 2}^{+1} \％$ $ $ 99 _ { - 2}^{+1} \％$。我们还使用此无激光门准备了钟状状态。相位门与常见误差源具有鲁棒性。我们研究了质量中心（COM）模式激发的效果，轴向陷阱频率中的误差，脉冲区域误差和序列时序中的误差。相位门的对比度没有显着降低到COM模式激发$ <20 $的声子，陷阱频率误差 +10％，脉冲面积误差为-8％。相移的最大影响不超过$ <10 $，脉冲面积错误为-2％。对比度和相位移位均可达到 - 定时误差最高-30％和 +15％。门实现是有效的，因为每个离子只需要一个单个驾驶场。此外，它通过通过改进的设置使用两种晶体的两个轴向运动模式来实现快速栅极速度（售价为$ 100〜μ $ s）的潜力。
We present the experimental implementation of a two-qubit phase gate, using a radio frequency (RF) controlled trapped-ion quantum processor. The RF-driven gate is generated by a pulsed dynamical decoupling sequence applied to the ions' carrier transitions only. It allows for a tunable phase shift with high-fidelity results, in particular a fringe contrast up to $99_{-2}^{+1}\%$ is observed in Ramsey-type measurements. We also prepare a Bell state using this laser-free gate. The phase gate is robust against common sources of error. We investigate the effect of the excitation of the center-of-mass (COM) mode, errors in the axial trap frequency, pulse area errors and errors in sequence timing. The contrast of the phase gate is not significantly reduced up to a COM mode excitation $<20$ phonons, trap frequency errors of +10%, and pulse area errors of -8%. The phase shift is not significantly affected up to $<10$ phonons and pulse area errors of -2%. Both, contrast and phase shift are robust to timing errors up to -30% and +15%. The gate implementation is resource efficient, since only a single driving field is required per ion. Furthermore, it holds the potential for fast gate speeds (gate times on the order of $100~μ$s) by using two axial motional modes of a two-ion crystal through improved setups.
