论文标题
超导量子处理器的高速校准和表征无需重置
High-speed calibration and characterization of superconducting quantum processors without qubit reset
论文作者
论文摘要
要表征和校准量子处理设备，必须收集大量的测量数据。主动量子重置增加了可以收集数据的速度，但需要其他硬件和/或校准。但是，实验设备可以以升高的重复速率运行，而无需重置。在这种情况下，首次测量的结果是下一个实验的初始状态。 ROL。 $ \ textit {et al。} $使用这种不安的操作模式通过测量构成$ x $门的Clifford Gates的固定长度序列来加速单量门的校准。修订版。 $ 7 $，041001（2017）]。但是，我们发现，在测量构成任意操作的脉冲序列时，在测量数据中会出现失真。在这里，我们通过展示如何有效分析不安的测量结果并正确扭曲以达到相同的结果和准确性，而与超导量子的重置相比，我们扩展了不安的方法。这使我们能够迅速表征和校准量子位。我们通过以$ 250〜 \ rm {kHz} $重复速率测量RABI振荡来说明我们的数据收集和分析方法，而无需重置，以衰减率为$ 1/2πt_1= 3〜 \ rm {kHz} $的量子。 我们还表明，与通过$ T_1 $ -DECAY重置量子的测量值相比，我们可以测量单个和两倍的平均栅极忠诚度，分别为20倍和8倍的基准测试。
To Characterize and calibrate quantum processing devices a large amount of measurement data has to be collected. Active qubit reset increases the speed at which data can be gathered but requires additional hardware and/or calibration. The experimental apparatus can, however, be operated at elevated repetition rates without reset. In this case, the outcome of a first measurement serves as the initial state for the next experiment. Rol. $\textit{et al.}$ used this restless operation mode to accelerate the calibration of a single-qubit gate by measuring fixed-length sequences of Clifford gates which compose to $X$ gates [Phys. Rev. Appl. $7$, 041001 (2017)]. However, we find that, when measuring pulse sequences which compose to arbitrary operations, a distortion appears in the measured data. Here, we extend the restless methodology by showing how to efficiently analyze restless measurements and correct distortions to achieve an identical outcome and accuracy as compared to measurements in which the superconducting qubits are reset. This allows us to rapidly characterize and calibrate qubits. We illustrate our data collection and analysis method by measuring a Rabi oscillation at a $250~\rm{kHz}$ repetition rate without any reset, for a qubit with a decay rate of $1/2πT_1=3~\rm{kHz}$. We also show that we can measure a single- and a two-qubit average gate fidelity with Randomized Benchmarking 20 and 8 times faster, respectively, than measurements that reset the qubits through $T_1$-decay.
