Topology, parity-time (PT) symmetry, and nonlinearity are at the origin of many fundamental phenomena in complex systems across the natural sciences, but their mutual interplay remains unexplored. We established a nonlinear non-Hermitian topological platform for active tuning of PT symmetry and topological states. We found that the loss in a topological defect potential in a non-Hermitian photonic lattice can be tuned solely by nonlinearity, enabling the transition between PT-symmetric and non–PT-symmetric regimes and the maneuvering of topological zero modes. The interaction between two apparently antagonistic effects is revealed: the sensitivity close to exceptional points and the robustness of non-Hermitian topological states. Our scheme using single-channel control of global PT symmetry and topology via local nonlinearity may provide opportunities for unconventional light manipulation and device applications.

拓扑，奇偶时间（PT）对称性和非线性是整个自然科学中复杂系统中许多基本现象的起源，但它们之间的相互作用尚未得到探索。我们建立了用于主动调整PT对称性和拓扑状态的非线性非Hermitian拓扑平台。我们发现，非Hermitian光子晶格中拓扑缺陷势的损失可以仅通过非线性来调整，从而可以在PT对称和非PT对称状态之间进行过渡，并且可以控制拓扑零模。揭示了两个明显的拮抗作用之间的相互作用：接近异常点的灵敏度和非Hermitian拓扑状态的鲁棒性。