论文标题
重新访问高阶特殊点的层次结构
Revisiting the hierarchical construction of higher-order exceptional points
论文作者
论文摘要
描述开放量子系统或波浪系统的非热汉尔顿人频谱中的高阶特殊点具有多种潜在应用，尤其是光学和光子学中。但是，众所周知，实验性实现是困难的。最近，Q. Zhong等人。 [物理。莱特牧师。 125，203602（2020）]引入了强大的结构，在该结构中，具有相同顺序的特殊点的两个子系统的单向耦合通常导致单个特殊点的单个特殊点的两倍。在这里，我们通过利用所涉及的汉密尔顿人的无可怜部分的努力来以不同的方式调查该计划。我们概括了该方案并得出了一个简单的公式，用于主持高阶特殊点的复合系统的光谱响应强度。讨论了其与子系统的光谱响应强度的关系。此外，我们研究了非肾上腺扰动。结果用一个示例说明了结果。
Higher-order exceptional points in the spectrum of non-Hermitian Hamiltonians describing open quantum or wave systems have a variety of potential applications in particular in optics and photonics. However, the experimental realization is notoriously difficult. Recently, Q. Zhong et al. [Phys. Rev. Lett. 125, 203602 (2020)] have introduced a robust construction where a unidirectional coupling of two subsystems having exceptional points of the same order leads generically to a single exceptional point of twice the order. Here, we investigate this scheme in a different manner by exploiting the nilpotency of the traceless part of the involved Hamiltonians. We generalize the scheme and derive a simple formula for the spectral response strength of the composite system hosting a higher-order exceptional point. Its relation to the spectral response strengths of the subsystems is discussed. Moreover, we investigate nongeneric perturbations. The results are illustrated with an example.
