We reveal how the vector field links are untied under the influence of anti-parity-time-symmetric couplings in a dissipative sublattice-symmetric topological photonic crystal lattice. The topology of the quasi-one-dimensional two-band system is encoded in the geometric topology of the vector fields associated with the Bloch Hamiltonian. The linked vector fields reflect the topology of the nontrivial phase. The topological phase transition occurs concomitantly with the untying of the vector field link at the exceptional points. Counterintuitively, more dissipation constructively creates a nontrivial topology. The linking number predicts the number of topological photonic zero modes.

中文翻译：

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通过反奇偶时间对称耦合解开链接

我们揭示了矢量场链接如何在耗散亚晶格对称拓扑光子晶体晶格中的反奇偶时间对称耦合的影响下解开。准一维二维系统的拓扑结构被编码在与布洛赫·哈密顿量相关的矢量场的几何拓扑结构中。链接的矢量场反映了非平凡相位的拓扑。拓扑相变与异常点处矢量场链接的解开同时发生。与直觉相反，更多的耗散会建设性地创建非平凡的拓扑。链接数可预测拓扑光子零模的数量。