High-sensitivity in various gyrator-based circuits with exceptional points of degeneracy
High-sensitivity in various gyrator-based circuits with exceptional points of degeneracy
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DOI：
10.1051/epjam/2022005
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发表时间：
2022
影响因子：
1.6
通讯作者：
K. Rouhi;A. Nikzamir;A. Figotin;F. Capolino
中科院分区：
文献类型：
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作者：
K. Rouhi;A. Nikzamir;A. Figotin;F. Capolino
异常简并点（EPD）可以使电路的灵敏度提高几个数量级。我们通过回转器耦合LC谐振器，支持EPD的二阶和三阶的各种配置。每个谐振器包括具有正值或负值的电容器和电感器，并且对应的EPD频率可以是真实的或虚的。当扰动发生在二阶EPD回转器为基础的电路，我们表明，有两个实值的频率从EPD的一个移动，遵循平方根定律。这与在奇偶时间（PT）对称电路中发生的情况相反，在该对称电路中，两个受扰动的谐振是复值的。我们展示了如何通过耦合两个不稳定的谐振器来获得稳定的EPD，如何获得具有虚频的不稳定的EPD，以及如何使用非对称回转器来获得具有真实的频率的EPD。相关的Puiironx分数幂级数展开显示了EPD的发生和电路对扰动的敏感性。我们的发现为新型高灵敏度设备铺平了道路，这些设备可用于感知物理，化学或生物变化。
Exceptional points of degeneracy (EPD) can enhance the sensitivity of circuits by orders of magnitude. We show various configurations of coupled LC resonators via a gyrator that support EPDs of second and third-order. Each resonator includes a capacitor and inductor with a positive or negative value, and the corresponding EPD frequency could be real or imaginary. When a perturbation occurs in the second-order EPD gyrator-based circuit, we show that there are two real-valued frequencies shifted from the EPD one, following a square root law. This is contrary to what happens in a Parity-Time (PT) symmetric circuits where the two perturbed resonances are complex valued. We show how to get a stable EPD by coupling two unstable resonators, how to get an unstable EPD with an imaginary frequency, and how to get an EPD with a real frequency using an asymmetric gyrator. The relevant Puiseux fractional power series expansion shows the EPD occurrence and the circuit's sensitivity to perturbations. Our findings pave the way for new types of high-sensitive devices that can be used to sense physical, chemical, or biological changes.