论文标题
具有高动态范围的量子处理器的读数Josephson参数放大器
Readout of a quantum processor with high dynamic range Josephson parametric amplifiers
论文作者
论文摘要
我们演示了一个高动态范围Josephson参数放大器（JPA），其中使用RF-SQUID数组实现了活动非线性元件。该设备与具有Klopfenstein-tager阻抗变压器的50 $ω$环境相匹配，并达到250-300 MHz的带宽，输入饱和功率在20 dB增益下高达-95 dbm。使用54 QUITIAL SYCAMORE处理器对这些设备进行基准测试，从而为读取功率提供了校准，添加噪声的估算值以及与单个DC-Squid的标准阻抗匹配的参数放大器进行比较的平台。我们发现，高功率RF-squid阵列设计对系统噪声，读数保真度或量度驱动没有不利影响，并且我们估计放大器上的上限以量子限制的1.6倍增加了噪声。最后，使用此设计的放大器显示出由于增益压缩而导致的读数保真度没有降解，这可能在传统JPA的多色调多路复用读数中发生。
We demonstrate a high dynamic range Josephson parametric amplifier (JPA) in which the active nonlinear element is implemented using an array of rf-SQUIDs. The device is matched to the 50 $Ω$ environment with a Klopfenstein-taper impedance transformer and achieves a bandwidth of 250-300 MHz, with input saturation powers up to -95 dBm at 20 dB gain. A 54-qubit Sycamore processor was used to benchmark these devices, providing a calibration for readout power, an estimate of amplifier added noise, and a platform for comparison against standard impedance matched parametric amplifiers with a single dc-SQUID. We find that the high power rf-SQUID array design has no adverse effect on system noise, readout fidelity, or qubit dephasing, and we estimate an upper bound on amplifier added noise at 1.6 times the quantum limit. Lastly, amplifiers with this design show no degradation in readout fidelity due to gain compression, which can occur in multi-tone multiplexed readout with traditional JPAs.
