Motion-induced directionality of collective emission in a non-chiral waveguide
Institute of Applied Physics, Technical University of Darmstadt（达姆施塔特工业大学应用物理研究所）；Dept. of Physics and research center OPTIMAS, RPTU University Kaiserslautern-Landau（凯泽斯劳滕-兰道理工大学物理系及OPTIMAS研究中心）
Yoan Spahn, Jens Hartmann, Benedikt Saalfrank, Michael Fleischhauer, Thomas Halfmann, Thorsten Peters
We report the experimental observation of motion-induced directionality in collective atomic emission within a hollow-core waveguide, establishing a general principle: directional interactions can emerge from collective phase engineering alone. Remarkably, neither single-emitter asymmetry nor any asymmetry in the geometric arrangement of the system is required - both the atom-field coupling and the spontaneous emission are fully isotropic in our system. Instead, Raman-induced effective two-level emitters with spatially oscillating transition dipole phases and atomic motion give rise to controllable directionality, reaching values up to 0.89(1). We study the correlations of the superfluorescent bursts close to and well above the threshold to collective emission; we find thermal statistics below and a buildup of coherence above it. Numerical simulations based on the Truncated Wigner Approximation for spins yield good agreement. Additionally we present a simple model based on position uncertainty capable of reproducing the observed directionality. Our results open a new route to directional interactions in non-chiral systems, with direct implications for the design of directional metamaterials and photonic structures built from isotropic constituents.
Fast and High Excitation Transport in Waveguide Quantum Electrodynamics
Institute of Atomic and Molecular Sciences, Academia Sinica（原子分子科学研究所，中央研究院）；Molecular Science and Technology Program, Taiwan International Graduate Program, Academia Sinica（分子科学与技术项目，台湾国际研究生计划，中央研究院）；Department of Physics, National Central University（物理系，中央大学）；Department of Physics and Center for Theoretical Physics, National Taiwan University（物理系与理论物理中心，国立台湾大学）；Center for Quantum Science and Engineering, National Taiwan University（量子科学与工程中心，国立台湾大学）；Physics Division, National Center for Theoretical Sciences（物理组，国家理论科学中心）
Directional and correlated optical emission from a waveguide-engineered molecule with local control
Center for Hybrid Quantum Networks (Hy-Q), Niels Bohr Institute, University of Copenhagen（哥本哈根大学尼尔斯·玻尔研究所混合量子网络中心）；Vienna Center for Quantum Science and Technology (VCQ) and Christian Doppler Laboratory for Photonic Quantum Computer, University of Vienna（维也纳大学维也纳量子科学与技术中心及光子量子计算机克里斯蒂安·多普勒实验室）；Experimental Physics VI, Faculty of Physics and Astronomy, Ruhr University Bochum（波鸿鲁尔大学物理与天文学系实验物理学第六研究室）
Input-output theory for waveguide QED with an ensemble of inhomogeneous atoms
我们研究了波导量子电动力学中出现的集体效应，其中几个（人工）原子耦合到一维超导传输线。由于单个微波光子可以沿着这条线无损耗地传播很长一段距离，因此一个原子发射的实光子和虚光子可以被另一个原子重新吸收或散射。根据原子之间的距离，这种集体效应可以导致超辐射和亚辐射，或者导致原子之间的相干交换型相互作用。改变人造原子的跃迁频率，这可以很容易地用超导量子比特（两级人造原子）完成，相当于改变原子-原子分离，从而打开了研究这些集体效应特征的可能性。为了研究这种波导量子电动力学系统，我们扩展了以前的工作，并提出了一个有效的主方程适用于一个相干态驱动的非均匀原子系综。使用输入-输出理论，我们计算分析和数值的弹性和非弹性散射，并显示这些数量如何揭示集体效应的信息。这些理论结果与最近使用transmon量子比特耦合到超导一维传输线的实验结果一致[A.~ F.~ van Loo { \it等人}]。
Emission of nitrogen-vacancy centers in diamond shaped by topological photonic waveguide modes
Department of Physics, CUNY- The City College of New York（纽约市立大学城市学院物理系）；Department of Electrical Engineering, CUNY-The City College of New York（纽约市立大学城市学院电气工程系）；CUNY-Graduate Center（纽约市立大学研究生院）；Center for Computational Quantum Physics, Flatiron Institute（Flatiron研究所计算量子物理中心）；Department of Physics BMS College of Engineering（BMS工程学院物理系）
Many-body enhancement of energy storage in a waveguide-QED quantum battery
Scuola Normale Superiore（高等师范学校）；QuSoft；Korteweg–de Vries Institute for Mathematics, University of Amsterdam（阿姆斯特丹大学科特维格-德弗里斯数学研究所）；JEIP, UAR 3573 CNRS, Collège de France, PSL Research University（法国国家科学研究中心第3573联合研究实验室，法兰西公学院，巴黎文理研究大学）；Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Padova（意大利国家核物理研究所帕多瓦分部）；Dipartimento di Fisica dell’Università di Pisa and INFN（比萨大学物理系及意大利国家核物理研究所）
Inhomogeneous Light-Matter Coupling as a Resource for Noiseless Quantum Memories
Centre for Quantum Technologies, Singapore（新加坡量子技术中心）；National University of Singapore, Department of Materials Science and Engineering, Singapore（新加坡国立大学材料科学与工程系）；National University of Singapore, Faculty of Science, Singapore（新加坡国立大学理学院）；MajuLab, CNRS-UCA-SU-NUS-NTU International Joint Research Laboratory（MajuLab，CNRS-南法大学-索邦大学-新加坡国立大学-南洋理工大学国际联合实验室）
