Fast High-Fidelity Quantum Nondemolition Qubit Readout via a Nonperturbative Cross-Kerr Coupling
Fast High-Fidelity Quantum Nondemolition Qubit Readout via a Nonperturbative Cross-Kerr Coupling
复制标题
DOI：
10.1103/physrevx.10.011045
复制
发表时间：
2020-02-25
影响因子：
12.5
通讯作者：
Buisson, O.
中科院分区：
文献类型：
--
作者：
Dassonneville, R.;Ramos, T.;Buisson, O.
量子位读出是任何量子信息处理器不可或缺的元素。在这项工作中，我们通过实验证明了跨振子模式和极化子模式之间的非微扰交叉克尔耦合，从而能够改进超导量子位的量子非破坏（QND）读出。新机制在色散近似中使用与标准 QND 量子位读出相同的实验技术，但由于其非微扰性质，它最大限度地提高了读出的速度、单次保真度和 QND 属性。此外，它还可以最大限度地减少不需要的衰变通道的影响，例如珀塞尔效应。我们观察到 50 ns 短脉冲的单次读出保真度为 97.4%，并且通过重复单次读出量化长测量脉冲的 QND 度为 99%。
Qubit readout is an indispensable element of any quantum information processor. In this work, we experimentally demonstrate a nonperturbative cross-Kerr couplingbetween a transmon and polariton mode which enables an improved quantum nondemolition (QND) readout for superconducting qubits. The new mechanism uses the same experimental techniques as the standard QND qubit readout in the dispersive approximation, but due to its nonperturbative nature, it maximizes the speed, the single-shot fidelity, and the QND properties of the readout. In addition, it minimizes the effect of unwanted decay channels such as the Purcell effect. We observe a single-shot readout fidelity of 97.4% for short 50-ns pulses and we quantify a QND-ness of 99% for long measurement pulses with repeated single-shot readouts.