Nonreciprocal coupling enables tunable exceptional-point response in non-Hermitian circuits
Abstract
Exceptional points (EPs) exhibit characteristic square-root spectral responses to weak perturbations, with response magnitudes governed by configuration-dependent prefactors that are often relatively small. Modulating these prefactor while preserving the exceptional characteristics offers an additional degrees of freedom for engineering non-Hermitian sensing responses. Here, we report a nonreciprocal non-Hermitian circuit system with gyrator-meditated coupling that supports a continuous family of EP configurations. Unlike reciprocal coupling, which typically yields a unique EP configuration for balanced gain and loss, nonreciprocal coupling allows the directional forward and backward coupling strengths to be varied while maintaining their product and thus preserving the EP condition and yielding a library of EPs. This additional freedom enables continuous control of the frequency-splitting magnitude without modifying the square-root characteristic dependence on absolute perturbation strength. We show that the spectral splitting induced by a given absolute resistance perturbation can be enhanced by appropriately adjusting the coupling asymmetry. Theoretical predictions, circuit simulations, and experimental reflection-spectrum measurements consistently confirms this tunable response. Our results establish nonreciprocal coupling as an alternative approach for engineering and enhancing EP-induced perturbative responses without changing their characteristic branch-point scaling.
Related
- Dynamics of entanglement in non-Hermitian system of nonreciprocal coupling
- Nonreciprocal Coupling Induced Non-Hermitian Entanglement in Optomechanical Systems
- Tunable non-Hermitian skin effect and topological phases in ladders with staggered nonreciprocal interleg hopping
- Nonreciprocal Floquet tunneling dynamics of spin-orbit-coupled bosonic atoms in a non-Hermitian double-well potential
- Controlling exceptional points of layered non-Hermitian structures with magnetic field
BibTeX
@misc{sha2026nonreciprocal,
title = {{Nonreciprocal coupling enables tunable exceptional-point response in non-Hermitian circuits}},
author = {Xiaoyin Sha and Chao Ma and Yuqi Jiang and Zhiqin Jiang and Junan Lai and Xiaoke Gao and Tianyu Dong},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.39157},
eprint = {2610.39157},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.39157},
}
RIS
TY - UNPB
TI - Nonreciprocal coupling enables tunable exceptional-point response in non-Hermitian circuits
AU - Xiaoyin Sha
AU - Chao Ma
AU - Yuqi Jiang
AU - Zhiqin Jiang
AU - Junan Lai
AU - Xiaoke Gao
AU - Tianyu Dong
PY - 2026
DA - 2026/10/29
PB - arXiv
DO - 10.48550/arxiv.2610.39157
UR - https://arxiv.org/abs/2610.39157
AB - Exceptional points (EPs) exhibit characteristic square-root spectral responses to weak perturbations, with response magnitudes governed by configuration-dependent prefactors that are often relatively small. Modulating these prefactor while preserving the exceptional characteristics offers an additional degrees of freedom for engineering non-Hermitian sensing responses. Here, we report a nonreciprocal non-Hermitian circuit system with gyrator-meditated coupling that supports a continuous family of EP configurations. Unlike reciprocal coupling, which typically yields a unique EP configuration for balanced gain and loss, nonreciprocal coupling allows the directional forward and backward coupling strengths to be varied while maintaining their product and thus preserving the EP condition and yielding a library of EPs. This additional freedom enables continuous control of the frequency-splitting magnitude without modifying the square-root characteristic dependence on absolute perturbation strength. We show that the spectral splitting induced by a given absolute resistance perturbation can be enhanced by appropriately adjusting the coupling asymmetry. Theoretical predictions, circuit simulations, and experimental reflection-spectrum measurements consistently confirms this tunable response. Our results establish nonreciprocal coupling as an alternative approach for engineering and enhancing EP-induced perturbative responses without changing their characteristic branch-point scaling.
ER -