Coupling a resonator to a superconducting qubit enables various operations on the qubit, including dispersive readout and unconditional reset. The speed of these operations is limited by the external decay rate of the resonator. However, increasing the decay rate also increases the rate of qubit decay via the resonator, limiting the qubit lifetime. Here, we demonstrate that the resonator-mediated qubit decay can be suppressed by utilizing the distributed-element, multi-mode nature of the resonator. We show that the suppression exceeds two orders of magnitude over a bandwidth of 600 MHz. We use this "intrinsic Purcell filter" to demonstrate a 40-ns readout with 99.1% fidelity and a 100-ns reset with residual excitation of less than 1.7%.
Multimode Purcell Filter for Superconducting-Qubit Reset and Readout with Intrinsic Purcell Protection
Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences（中国科学院物理研究所凝聚态物理北京国家实验室）；School of Physical Sciences, University of Chinese Academy of Sciences（中国科学院大学物理科学学院）
Flexible Readout and Unconditional Reset for Superconducting Multi-Qubit Processors with Tunable Purcell Filters
Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences（中国科学院物理研究所凝聚态物理北京国家实验室）；School of Physics, University of Chinese Academy of Sciences（中国科学院大学物理学院）
Broadband Purcell Filter for Fast Superconducting Qubit Reset and Readout
Key Laboratory of Atomic and Subatomic Structure and Quantum Control (South China Normal University), Ministry of Education, Guangdong Basic Research Center of Excellence for Structure and Fundamental Interactions of Matter, School of Physics, South China Normal University（华南师范大学物理学院）；International Quantum Academy（国际量子学院）；School of Emerging Technology, University of Science and Technology of China（中国科学技术大学前沿技术学院）；Southern University of Science and Technology（南方科技大学）；Institute of Micro and Nano Optoelectronics, Shenzhen University（深圳大学微纳光电子研究院）
Ideal Quantum Nondemolition Readout of a Flux Qubit Without Purcell Limitations
在量子计算中，基于Rabi模型的大失谐色散耦合被广泛用于量子非破坏（QND）量子比特读出。然而，测量速度和保真度通常受到Purcell效应的显著限制，即：Purcell衰变，临界光子数和依赖于量子位的克尔非线性。为了避免这些影响，我们提出了如何实现一个理想的QND读出的梯度通量量子比特与可调间隙通过其非微扰色散耦合（NPDC）的频率可调测量谐振器。我们表明，这种基于NPDC的读出机制是免费的偶极场相互作用，量子比特QND测量不恶化腔内光子。量子位读出速度和保真度都可以\emph{avoid the Purcell limitations}。此外，NPDC可以方便地打开和关闭通过外部控制通量。我们将展示如何将此建议扩展到多量子位架构的联合量子位读出。
Quantum theory of a bandpass Purcell filter for qubit readout
超导transmon和Xmon量子比特的读出保真度部分地受到通过谐振器进入传输线的量子比特能量弛豫的限制，这也被称为珀塞尔效应。抑制这种能量弛豫的一种方法是采用滤波器，该滤波器阻止量子比特频率下的微波传播。本文对E.杰弗里\textit{et al} [物理学]修订版本\ Lett. 112，190504（2014）]。对于典型的实验参数，带通滤波器抑制量子比特弛豫速率高达两个数量级，同时保持相同的测量速率。我们还表明，在微波驱动的存在下，量子比特的弛豫率进一步降低，随着驱动强度的增加。
A scalable edge-pass Purcell filter for high-fidelity readout of superconducting qubits
National Laboratory of Solid State Microstructures, School of Physics, Nanjing University（南京大学固体微结构物理学院）；Shishan Laboratory, Nanjing University（南京大学狮山实验室）；Jiangsu Key Laboratory of Quantum Information Science and Technology, Nanjing University（南京大学江苏省量子信息科学与技术重点实验室）；Tencent Quantum Laboratory, Tencent（腾讯量子实验室）
Dark state as a measurable state by a dispersive readout without a Purcell limit
National Chung Hsing University（中兴大学）；Feng Chia University（逢甲大学）；Research Center for Critical Issues, Academia Sinica（中央研究院关键问题研究中心）；National Changhua University of Education（国立彰化师范大学）
Design of Qubit Readout Circuit for Purcell-Rate Suppression by Two-Path Interference
Ankara Yildirim Beyazit University（安卡拉耶尔德勒姆·贝亚济特大学）；Iranian Quantum Technologies Research Center (IQTEC)（伊朗量子技术研究中心）；K.N. Toosi University of Technology（K.N.图西理工大学）；Kharazmi University（哈拉兹米大学）
本文提出一种量子比特先耦合滤波谐振器再耦合读出谐振器的新型读出电路，通过调节谐振器-滤波器耦合强度精确控制 Purcell 衰减率和 ac Stark 因子，在提高量子比特状态可区分性的同时保持输出信号的非经典性。
Single-step phase-engineered pulse for active readout cavity reset with a known qubit state
University of Science and Technology of China（中国科学技术大学）；Laboratory of Quantum Information, University of Science and Technology of China（中国科学技术大学量子信息实验室）；Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China（中国科学技术大学量子信息与量子科技创新中心）；Suzhou Institute for Advanced Research, University of Science and Technology of China（中国科学技术大学苏州高等研究院）
A Compact Broadband Purcell Filter for Superconducting Quantum Circuits in a 3D Flip-Chip Architecture
Technical University of Munich（慕尼黑工业大学）；Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften（瓦尔特·迈斯纳研究所，巴伐利亚科学院）；Fraunhofer EMFT Institute for Electronic Microsystems and Solid State Technologies（弗劳恩霍夫电子微系统和固态技术研究所）
Readout-Induced Leakage in Superconducting Circuits with Nonlinear Couplings
Yale University（耶鲁大学）；Yale Quantum Institute, Yale University（耶鲁量子研究所，耶鲁大学）；University of California Santa Barbara（加州大学圣塔芭芭拉分校）；Google Quantum AI（谷歌量子AI）
