AI 中文总结
研究旋磁光子晶体中有偏随机磁通诱导的拓扑相变，通过随机取向旋磁棒磁化方向实现无序哈代模型，证明磁通密度平衡时带隙关闭、引入净磁通时重新打开，可视化边缘态反转，建立独特无序驱动机制。
AI 中文摘要
无序与拓扑态之间的相互作用引起了越来越多的关注。以往研究主要关注几何或势场随机性的影响，而由随机磁通驱动的拓扑相变在实验上仍难以实现。本文报道了在旋磁光子晶体中首次通过有偏随机磁通实现拓扑相变的实验。通过随机取向组成旋磁棒的磁化方向，实现了一个无序的哈代模型，其中次近邻跳跃相位的符号随机分布。我们证明，当正、负磁通密度平衡时，即从统计意义上恢复时间反演对称性时，体带隙关闭；当引入净正或负磁通时，体带隙重新打开。微波近场测量直接可视化了手性边缘态的反转，证实了不同拓扑相之间的转变。我们的结果建立了一种独特的无序驱动机制来实现拓扑相变，并加深了我们对玻色子系统中无序与拓扑相之间相互作用的理解。
英文摘要
The interplay between disorder and topological states has attracted growing interest. While previous studies have primarily addressed the effects of geometric or potential randomness, the exploration of topological phase transitions driven by random-flux remains experimentally elusive. Here, we report the first experimental realization of topological phase transitions driven by biased random-flux in gyromagnetic photonic crystals. By stochastically orienting the magnetization of constituent gyromagnetic rods, we implement a disordered Haldane model in which the sign of the next-nearest-neighbor hopping phases is randomly distributed. We demonstrate that the bulk band gap closes when the densities of positive and negative flux are balanced, i.e, restoring time-reversal symmetry in a statistical sense, and reopens when a net positive or negative flux is introduced. Microwave near-field measurements directly visualize the reversal of chiral edge states, confirming a transition between distinct topological phases. Our results establish a unique disorder-driven mechanism for realizing topological phase transitions and deepen our understanding of the interplay between disorder and topological phases in bosonic systems.
