2024/06/28 by S. M. Rafi‐Ul‐Islam, Rafi-Ul-Islam, S. M., Zhuo Bin Siu +5 · 2 citations
Neuroscience · Physics and Astronomy · #Atomic and Subatomic Physics Research #FOS: Physical sciences #Mechanical and Optical Resonators #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Photoreceptor and optogenetics research #Quantum Physics (quant-ph)
paper · pdf · doi:10.48550/arxiv.2406.19629
openalex publication_date 2024/06/28 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
A class of non-Hermitian topological sensors (NTOSs) was recently proposed in which the NTOS comprises a non-Hermitian Su-Schrieffer-Heeger chain with a measurant-dependent coupling between the two ends of the chain. The smallest eigenenergy of the system, which serves as the readout signal, has an exponential dependence on the system size at small system sizes but saturates above a critical size. In this study, we further elucidate the dependence of the sensor sensitivity and saturation behavior on the system parameters. We explain how the behavior of the NTOS is characterized by a winding number, which indicates whether the smallest eigenenergy decreases to zero exponentially with the system size or grows exponentially up to a critical size. Interestingly, we further show that by imposing unidirectionality on the coupling between the two ends of a sensor, we can flip the size dependence of the smallest eigenenergy value from an exponentially increasing trend to an exponentially decreasing one. Our findings provide important insights into the saturation phenomenon and the impact of terminal couplings on the sensing characteristics of NTOSs.