High-order exceptional points and stochastic resonance in pseudo-Hermitian systems

TL;DR

This paper explores high-order exceptional points in pseudo-Hermitian systems, revealing their potential for enhanced sensing through stochastic resonance and broad frequency responses, advancing sensor technology applications.

Contribution

It develops a theoretical framework for high-order exceptional points, analyzing their stochastic dynamics and uncovering unique resonance behaviors for improved sensing performance.

Findings

Identification of three types of frequency responses to perturbations

Discovery of a broad stochastic resonance with high SNR at various noise levels

Potential applications in signal processing and sensor technology

Abstract

Exceptional points, a remarkable phenomenon in physical systems, have been exploited for sensing applications. It has been demonstrated recently that it can also utilize as sensory threshold in which the interplay between exceptional-point dynamics and noise can lead to enhanced performance. Most existing works focused on second-order exceptional points. We investigate the stochastic dynamics associated with high-order exceptional points with a particular eye towards optimizing sensing performance by developing a theoretical framework based on pseudo-Hermiticity. Our analysis reveals three distinct types of frequency responses to external perturbations. A broad type of stochastic resonance is uncovered where, as the noise amplitude increases, the signal-to-noise ratio reaches a global maximum rapidly but with a slow decaying process afterwards, indicating achievable high performance in a wide range of the noise level. These results suggest that stochastic high-order exceptional-point dynamics can be exploited for applications in signal processing and sensor technologies.