Non-Hermitian CT-Symmetric Spectral Protection of Nonlinear Defect Modes

Topological defect engineering and PT-symmetry in non-Hermitian electrical circuits

We employ electric circuit networks to study topological states of matter in non-Hermitian systems enriched by parity-time symmetry $\mathcal{PT}$ and chiral symmetry anti-$\mathcal{PT}$ ($\mathcal{APT}$). The topological structure manifests itself in the complex admittance bands which yields excellent measurability and signal to noise ratio. We analyze the impact of $\mathcal{PT}$ symmetric gain and loss on localized edge and defect states in a non-Hermitian Su--Schrieffer--Heeger (SSH) circuit. We realize all three symmetry phases of the system, including the $\mathcal{APT}$ symmetric regime…

非厄米缺陷诱导的无标度局域态的观测

Observation of scale-free localized states induced by non-Hermitian defects

本研究利用电路晶格实验观测到非厄米缺陷诱导的无标度局域态，表明其局域长度随系统尺寸线性变化，并源于宇称-时间对称性的自发破缺。

用于空间与时空局域化的缺陷非厄米谐振子二聚体链设计

Design of defected non-hermitian chains of resonator dimers for spatial and spatio-temporal localizations

本文提出设计高对比度非厄米超材料的公式，通过特征方程和显式参数公式实现静态与瞬时变化缺陷二聚体材料中指定亚波长缺陷模态频率的设计，并构造出时空局域化缺陷模态。

Emergence of Exceptional Points in Periodic Metastructures with Hidden PT-symmetric Defects

We study the elastodynamics of a periodic metastructure incorporating a defect pair that enforces a parity-time (PT) symmetry due to a judiciously engineered imaginary impedance elements - one having energy amplification (gain) and the other having an equivalent attenuation (loss) mechanism. We show that their presence affects the initial band structure of the periodic Hermitian metastructure and leads to the formation of numerous exceptional points (EPs) which are mainly located at the band edges where the local density of modes is higher. The spatial location of the PT-symmetric defect serve…

Sensitivity of topological edge states in a non-Hermitian dimer chain

Photonic topological edge states in one-dimensional dimer chains have long been thought to be robust to structural perturbations by mapping the topological Su-Schrieffer-Heeger model of a solid-state system. However, the edge states at the two ends of a finite topological dimer chain will interact as a result of near-field coupling. This leads to deviation from topological protection by the chiral symmetry from the exact zero energy, weakening the robustness of the topological edge state. With the aid of non-Hermitian physics, the splitting frequencies of edge states can be degenerated again a…

球形非厄米拓扑电路中的能量局域化

Energy Localization in Spherical Non-Hermitian Topolectrical Circuits

本研究通过球形剖分模型与MaxWSC方法，在非厄米SSH链中探究拓扑缺陷引发的能量局域化，并经PCB实验验证，展示了非欧几何在NHSE研究中的潜力。