论文标题
非线性启用了高维的异常拓扑
Nonlinearity enabled higher-dimensional exceptional topology
论文作者
论文摘要
非线性在拓扑中的作用已在Hermitian系统中进行了广泛研究，而非线性仅被用作PT对称非官方系统中的调谐旋钮。在这里，在我们的工作中，我们表明非线性在形成非热式系统的拓扑奇异性方面起着至关重要的作用。我们通过使用理论和电路实验进行了一个简单而直观的示例，这是一个具有杂交拓扑不变性（HTI）的高阶特殊点（EX），它仅在两个借助非线性增益的耦合谐振器中。构建了相位刚度以确认我们的非线性系统中的HTI，并且通过实验验证了特征百叶窗的各向异性临界行为。我们的发现导致了对非线性非热性系统特殊拓扑的基本理解的进步，这可能是为应用开放的新途径。
The role of nonlinearity on topology has been investigated extensively in Hermitian systems, while nonlinearity has only been used as a tuning knob in a PT symmetric non-Hermitian system. Here, in our work, we show that nonlinearity plays a crucial role in forming topological singularities of non-Hermitian systems. We provide a simple and intuitive example by demonstrating with both theory and circuit experiments an exceptional nexus (EX), a higher-order exceptional point with a hybrid topological invariant (HTI), within only two coupled resonators with the aid of nonlinear gain. Phase rigidities are constructed to confirm the HTI in our nonlinear system, and the anisotropic critical behavior of the eigenspectra is verified with experiments. Our findings lead to advances in the fundamental understanding of the peculiar topology of nonlinear non-Hermitian systems, possibly opening new avenues for applications.
