Arbitrary-order exceptional points in a nanomechanical cavity

TL;DR

This paper demonstrates a scalable nanomechanical system capable of realizing and studying arbitrary-order exceptional points, revealing enhanced sensitivity and noise amplification effects.

Contribution

It introduces a novel architecture for implementing high-order exceptional points using a single nanomechanical resonator with virtual resonators, enabling scalable and robust experimental exploration.

Findings

Realized up to seventh-order exceptional points experimentally.

Confirmed identical amplification of signal and noise near EPs.

Established a platform for studying higher-order EP phenomena.

Abstract

Higher-order exceptional points (EPs) govern non-Hermitian system dynamics through their enriched and sharpened spectral topology, yet the intrinsic topological fragility hinders robust experimental realization. Here, we present a scalable architecture that implements arbitrary-order EPs via a recurrent network comprising a single nanomechanical resonator and unlimited virtual resonators. We experimentally realize mechanical EPs up to the seventh order and confirm this architecture's scalability. Moreover, we reveal that the fundamental noise component and the measured signal share the same system coupling channel and thus undergo identical root-response amplification near EPs of arbitrary order, consistent with our signal-to-noise ratio measurements. Our work establishes a general platform for exploring higher-order EP-based phenomena while clarifying the fundamental boundary of non-Hermitian sensitivity enhancement across diverse physical systems.