When overlapping in an optical medium with nonlinear susceptibility, light waves can interact with each other, changing their phases, wavelengths, shapes, and so on. Such nonlinear effects, discovered over a half century ago, have given rise to a breadth of important applications. Applying to quantum-mechanical signals, however, they face fundamental challenges arising from the multimode nature of the interacting electromagnetic fields, such as phase noises and Raman scattering. Quantum Zeno blockade allows strong interaction of light waves without them physically overlapping, thus providing a viable solution for those challenges, as indicated in recent bulk-optics experiments. Here, we report on the observation of quantum Zeno blockade on chip, where a light wave is modulated by another in a distinct "interaction-free" manner. For quantum applications, we also verify its operations on a single-photon level. Our results promise a scalable platform for overcoming several grand challenges faced by nonlinear optics and quantum information processing, enabling, e.g., manipulation and interaction of quantum signals without decoherence.
Triply Resonant Photonic Crystal Nanobeam Cavities for Unconditional Photon Blockade
Department of Physics, University of Washington（华盛顿大学物理系）；Department of Electrical and Computer Engineering, University of Washington（华盛顿大学电气与计算机工程系）；Pritzker School of Molecular Engineering, University of Chicago（芝加哥大学普里茨克分子工程学院）；CUNY Graduate Center（纽约市立大学研究生中心）；Department of Physics, University of Massachusetts, Dartmouth（麻省大学达特茅斯分校物理系）；Center for Scientific Computing and Data Science Research, University of Massachusetts, Dartmouth（麻省大学达特茅斯分校科学计算与数据科学研究中心）
Photon Anomalous Blockade in Waveguide Cavity QED with Atomic Mirrors
School of integrated circuits, Tsinghua University（清华大学集成电路学院）；Beijing Automation Control Equipment Institute（北京自动化控制设备研究所）；Institute of Theoretical Physics, Chinese Academy of Sciences（中国科学院理论物理研究所）；CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences（中国科学院大学拓扑量子计算卓越创新中心）；Frontier Science Center for Quantum Information（量子信息前沿科学中心）
Unconventional phonon blockade via atom-photon-phonon interaction in hybrid optomechanical systems
声子非线性在混合量子网络和片上量子器件中起着重要的作用。研究了由一个原子和一个或两个标准光机械腔组成的混合系统中机械振子的声子统计。通过原子-光子-声子三方相互作用可以得到有效增强的原子-声子相互作用，其中原子-光子耦合取决于机械位移，而实际上不改变腔频率。这种新的光机械相互作用机制，如Cotrufo等人最近预测的[Phys. Rev. Lett. 118，133603（2017）]，与标准的有根本的不同。在增强的原子-声子耦合作用下，在原弱耦合区产生了强的单激发态声子非线性，导致声子阻塞现象的出现。此外，给出了单腔和双腔情况下的最优参数范围.我们比较了单腔杂化系统中不同阶次的声子数关联函数，揭示了声子诱导隧穿和不同类型声子阻塞的发生.我们的方法提供了一个替代的方法来产生和控制单声子的量子制度，并在单声子量子技术的潜在应用。
