In the known field of topological photonics, what remains less so is the breakdown effect of topological phases deteriorated by perturbation. In this study, the authors investigate the variance on topological invariants for a periodic Kekulé medium perturbed in unit cells, which was a gyromagnetic photonic crystal holding topological phases induced by synchronised rotation of unit cells. Two parameters for geometric and material perturbation are respectively benchmarked to characterise the topological degradation. Our calculation demonstrates that such a periodic perturbation easily destructs the topological phase and thus calls for further checkups on robustness under such unit-cell-perturbation in realisation.

中文翻译：

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旋磁光子晶体中周期性扰动对拓扑相鲁棒性的击穿效应


在已知的拓扑光子学领域，由于扰动而恶化的拓扑相的击穿效应仍然不那么重要。在这项研究中，作者研究了晶胞中扰动的周期性凯库勒介质的拓扑不变量的方差，该介质是一种旋磁光子晶体，具有由晶胞同步旋转引起的拓扑相位。分别以几何和材料扰动的两个参数为基准来表征拓扑退化。我们的计算表明，这种周期性扰动很容易破坏拓扑相，因此需要在实现时进一步检查这种晶胞扰动下的鲁棒性。