Observation of Universal Spectral Moments and the Dynamic Dispersive-to-Proliferative Transition

Fuente: arXiv
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Main Authors: Zhong, Jia-Xin, Shu, Chang, Cheng, Nan, Kim, Jee Woo, Zhang, Kai, Sun, Kai, Jing, Yun
Format: Preprint
Published: 2026
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author Zhong, Jia-Xin
Shu, Chang
Cheng, Nan
Kim, Jee Woo
Zhang, Kai
Sun, Kai
Jing, Yun
author_facet Zhong, Jia-Xin
Shu, Chang
Cheng, Nan
Kim, Jee Woo
Zhang, Kai
Sun, Kai
Jing, Yun
contents In non-Hermitian systems, spectra can be maximally boundary-sensitive, yet bulk physics need not be. Here we experimentally show that spectral moments provide boundary-robust bulk observables in finite non-Hermitian lattices, even when the spectra undergo dramatic geometry-dependent reshaping due to the skin effect. Using a unified acoustic platform with full spectral reconstruction and time-domain access, we probe one-, two- and three-dimensional lattices and demonstrate that spectral moments remain nearly invariant across distinct boundary geometries while the corresponding complex spectra differ strongly. To connect the thermodynamic theorem to realistic finite systems, we develop a loop-counting theory that identifies the physical origin of finite-size deviations in terms of missing boundary loops, quantitatively captures the corrections, and predicts a scaling law, which we verify experimentally. Beyond acoustic spectroscopy, we reveal a counterintuitive dynamical consequence of moment invariance: a dispersive-to-proliferative bulk transition governed by bulk moment structure rather than spectral boundary sensitivity. As a result, local bulk dynamics can remain stable (dispersive) even in a $\mathcal{PT}$-broken spectral regime, challenging the conventional expectation that $\mathcal{PT}$ breaking necessarily implies feedback-induced dynamical instability (proliferation) through exponentially amplifying spectral components. These results establish spectral moments as practical bulk descriptors for finite non-Hermitian matter and open a route to extracting and controlling intrinsic bulk behavior in realistic wave-based non-Hermitian devices.
format Preprint
id arxiv_https___arxiv_org_abs_2604_27585
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Observation of Universal Spectral Moments and the Dynamic Dispersive-to-Proliferative Transition
Zhong, Jia-Xin
Shu, Chang
Cheng, Nan
Kim, Jee Woo
Zhang, Kai
Sun, Kai
Jing, Yun
Quantum Physics
Mesoscale and Nanoscale Physics
In non-Hermitian systems, spectra can be maximally boundary-sensitive, yet bulk physics need not be. Here we experimentally show that spectral moments provide boundary-robust bulk observables in finite non-Hermitian lattices, even when the spectra undergo dramatic geometry-dependent reshaping due to the skin effect. Using a unified acoustic platform with full spectral reconstruction and time-domain access, we probe one-, two- and three-dimensional lattices and demonstrate that spectral moments remain nearly invariant across distinct boundary geometries while the corresponding complex spectra differ strongly. To connect the thermodynamic theorem to realistic finite systems, we develop a loop-counting theory that identifies the physical origin of finite-size deviations in terms of missing boundary loops, quantitatively captures the corrections, and predicts a scaling law, which we verify experimentally. Beyond acoustic spectroscopy, we reveal a counterintuitive dynamical consequence of moment invariance: a dispersive-to-proliferative bulk transition governed by bulk moment structure rather than spectral boundary sensitivity. As a result, local bulk dynamics can remain stable (dispersive) even in a $\mathcal{PT}$-broken spectral regime, challenging the conventional expectation that $\mathcal{PT}$ breaking necessarily implies feedback-induced dynamical instability (proliferation) through exponentially amplifying spectral components. These results establish spectral moments as practical bulk descriptors for finite non-Hermitian matter and open a route to extracting and controlling intrinsic bulk behavior in realistic wave-based non-Hermitian devices.
title Observation of Universal Spectral Moments and the Dynamic Dispersive-to-Proliferative Transition
topic Quantum Physics
Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2604.27585