Title: Superluminal Correlations in Ensembles of Optical Phase Singularities Show Chinese title

Title: 超光速关联在光学相位奇点集合中

Abstract: Phase singularities are universal features found across diverse wave systems. Their ensembles exhibit distance correlations governing exotic material phases. However, the full correlations in phase-space have remained unexplored and experimentally inaccessible. Here, we directly measure the ultrafast dynamics of optical singularity ensembles, capturing their phase-space correlations. Our observations reveal that phase singularities exhibit acceleration to unbounded velocities before annihilation, indicated by measurements of velocities exceeding the speed of light. These superluminal velocities are paradoxically amplified by the slow group velocity of hyperbolic phonon polaritons in our material platform, hexagonal boron nitride membranes. We demonstrate these phenomena using combined hardware and algorithmic advances in ultrafast electron microscopy, achieving spatial and temporal resolutions each an order of magnitude below the polaritonic wavelength and cycle period. Our findings enable probing topological defect dynamics at previously unattainable timescales, deepening our understanding of phase-singularity universality and suggesting phenomena of ultrafast information flow in polaritonic media. Show Chinese abstract

Abstract: 相位奇点是跨多种波系统普遍存在的特征。它们的集合表现出距离相关性，控制着奇特的材料相。然而，相空间中的完整相关性一直未被探索且实验上不可访问。在这里，我们直接测量了光学奇点集合的超快动力学，捕捉到了它们的相空间相关性。我们的观察结果表明，相位奇点在湮灭前表现出加速到无限速度的现象，这由超过光速的速度测量所指示。这些超光速速度在我们材料平台——六方氮化硼膜中，通过双曲声子极化子的慢群速度而矛盾地被放大。我们通过超快电子显微镜的硬件和算法进步相结合，展示了这些现象，实现了空间和时间分辨率，分别低于极化子波长和周期的一个数量级。我们的发现使得在以前无法达到的时间尺度上探测拓扑缺陷动力学成为可能，加深了我们对相位奇点普遍性的理解，并暗示了极化子介质中超快信息流的现象。