由传输子环控制的超导微波腔的光子态为量子信息的编码和操纵提供了一个平台。扩大平台规模的一个关键挑战是需要在腔体之间按需通信信息。最近已经证明，两个腔之间的可调谐双线性相互作用可以通过将它们耦合到双色驱动的transmon辅助来实现，这允许交换和干涉腔的多光子状态[Gao等人，Phys. Rev. X 8，021073（2018）]。在这里，我们从理论上和实验上探索了实现快速SWAP门所需的辅助上的相对较强的驱动器的制度，但这也可能导致不希望的非微扰效应，降低SWAP保真度。我们开发了一个理论形式主义的基础上，线性响应理论，允许一个计算率的辅助诱导的相互作用，衰减和频率偏移的腔的磁化率矩阵。我们对待的驱动器非微扰使用Floquet理论，并发现，这两个驱动器的干扰可以强烈地改变系统的动态，即使在该政权的旋转波近似适用。我们确定了两个主要来源的不忠，由于附属退相干。i）辅助耗散和退相导致Floquet态之间的不相干跳跃，即使当辅助处于零温度时也会发生这种不相干跳跃，从而导致SWAP速率的突然变化。ii）腔通过逆Purcell效应从相对有损耗的辅助部分继承有限衰减;当驱动引起的AC斯塔克位移将某些辅助部分过渡频率推到腔频率附近时，可以增强该效应。理论预测与实验结果在数量上一致，为使用该理论设计未来的实验铺平了道路。
英文摘要：
Photonic states of superconducting microwave cavities controlled by transmon ancillas provide a platform for encoding and manipulating quantum information. A key challenge in scaling up the platform is the requirement to communicate on demand the information between the cavities. It has been recently demonstrated that a tunable bilinear interaction between two cavities can be realized by coupling them to a bichromatically-driven transmon ancilla, which allows swapping and interfering the multi-photon states of the cavities [Gao et al., Phys. Rev. X 8, 021073(2018)]. Here, we explore both theoretically and experimentally the regime of relatively strong drives on the ancilla needed to achieve fast SWAP gates but which can also lead to undesired non-perturbative effects that lower the SWAP fidelity. We develop a theoretical formalism based on linear response theory that allows one to calculate the rate of ancilla-induced interaction, decay and frequency shift of the cavities in terms of a susceptibility matrix. We treat the drives non-perturbatively using Floquet theory, and find that the interference of the two drives can strongly alter the system dynamics even in the regime where the rotating wave approximation applies. We identify two major sources of infidelity due to ancilla decoherence. i) Ancilla dissipation and dephasing leads to incoherent hopping among Floquet states which occurs even when the ancilla is at zero temperature, resulting in a sudden change of the SWAP rate. ii) The cavities inherit finite decay from the relatively lossy ancilla through the inverse Purcell effect; the effect can be enhanced when the drive-induced AC Stark shift pushes certain ancilla transition frequencies to the vicinity of the cavity frequencies. The theoretical predictions agree quantitatively with the experimental results, paving the way for using the theory to design future experiments.
Engineering the unitary charge-conjugation operator of quantum field theory for particle-antiparticle using trapped ions and light fields in cavity QED
Engineering protected cavity-QED interactions through pulsed dynamical decoupling
University of the Basque Country UPV/EHU（巴斯克地区大学）；Instituto de Física Teórica, UAM-CSIC, Universidad Autónoma de Madrid（马德里自治大学理论物理研究所）；Quantronics Group, SPEC, CEA Saclay, CNRS, Université Paris-Saclay（巴黎综合理工学院集团、SPEC、CEA萨克雷、CNRS、巴黎萨克雷大学）；Department of Physics, ETH Zürich（苏黎世联邦理工学院物理系）；Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften（瓦尔特·迈斯纳研究所，巴伐利亚科学院）；Technische Universität München, TUM School of Natural Sciences, Physics Department（慕尼黑工业大学自然科学学院物理系）；Munich Center for Quantum Science and Technology (MCQST)（慕尼黑量子科学与技术中心）
Photonic state engineering via energy-level crossing by giant atoms in topological waveguide QED setup
School of Physics Science and Technology, Shenyang Normal University（沈阳师范大学物理科学与技术学院）；School of Physical Science and Technology, Soochow University（苏州大学物理科学与技术学院）；Center for Quantum Sciences and School of Physics, Northeast Normal University（东北师范大学量子科学中心与物理学院）
An extensive theory of nonlinearly intercoupled pseudomodes for noise model reduction in circuit QED
University of Texas, San Antonio（德克萨斯大学圣安东尼奥分校）；UCLA（加州大学洛杉矶分校）；College of Letters and Science, University of California, Los Angeles（加州大学洛杉矶文理学院）；Qblox B.V.（Qblox有限公司）
Broadening the reflection band of atomic mirrors by engineering the emitter-waveguide coupling
National Center for Theoretical Sciences（国家理论科学中心）；Hon Hai Research Institute（鸿海研究院）；National Taiwan University（台湾大学）；Academia Sinica（中央研究院）；National Central University（中央大学）
Generation of decoherence-free displaced squeezed states of radiation fields and a squeezed reservoir for atoms in cavity QED
我们提出了一种方法来设计一个有效的反Jaynes-Cumming和Jaynes-Cumming原子系统和单腔模式之间的相互作用，并展示了如何在油藏工程过程中使用它。为了构造有效哈密顿量，我们分析了在经典场驱动下，处于λ位形的原子系统与单腔模的相互作用.利用这种相互作用，我们首次给出了如何产生无消相干的腔场位移压缩态。在我们的方案中，原子束作为一个水库的辐射场被困在腔内，最近所采用的S。Pielawa等人[Phys. Rev. Lett. 98，240401（2007）]以在高Q谐振器中产生爱因斯坦-波多尔斯基-罗森纠缠辐射态。在我们的方案中，所有的原子都必须在基态下准备，并且如在引用的文章中那样，既不需要原子检测，也不需要原子与腔模之间的精确相互作用时间。从这种相互作用中，我们也可以为原子系统生成一个理想的压缩库。为此，我们必须假设，除了工程原子-场相互作用之外，腔场的强衰减（即，腔衰减必须比有效的原子-场耦合强得多）。利用这个方案，可以检验压缩库中原子动力学中的一些有趣的效应。
Phase-Selected Efficient Single-Photon Frequency Conversion via Local Fano Resonance in a Two-Giant-Atom Waveguide-QED System
Key Laboratory of Opto-electronic Control and Detection Technology of University of Hunan Province, and College of Physics and Electronic Engineering, Hengyang Normal University（衡阳师范学院光电控制与检测技术湖南省重点实验室及物理与电子工程学院）；Key Laboratory of Low Dimensional Quantum Structures and Quantum Control of Ministry of Education，Hunan Normal University（湖南师范大学教育部低维量子结构与量子控制重点实验室）
Autonomous Stabilization of Floquet States Using Static Dissipation
Department of Physics, Stanford University（斯坦福大学物理系）；Department of Physics, Boston University（波士顿大学物理系）；Max-Planck-Institut für Physik komplexer Systeme（马克斯·普朗克复杂系统物理研究所）
