Probing Chaos and Criticality with Observational Entropy and Finite-Resolution Measurements

Fuente: arXiv
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Main Authors: Kannan, J. Bharathi, PG, Sreeram, Santhanam, M. S.
Format: Preprint
Published: 2026
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author Kannan, J. Bharathi
PG, Sreeram
Santhanam, M. S.
author_facet Kannan, J. Bharathi
PG, Sreeram
Santhanam, M. S.
contents Coarse-grained measurements offer a scalable alternative to full state tomography for characterizing complex quantum dynamics. We show that observational entropy (OE), an information-theoretic entropy defined directly from finite-resolution measurement outcomes, provides a unified and experimentally accessible framework for quantifying chaos and probing criticality. From probing the insulator-metal crossover in the Aubry-Andre model to tracking the gradual destruction of Kolmogorov-Arnold-Moser tori in the Kicked Rotor, derivatives of OE provide an accurate and unified diagnostic of probing these transitions. In both cases, the critical points extracted from dynamical evolution and eigenstate analyses converge to the exact theoretical values once the observational resolution exceeds a finite threshold. In the chaotic limit, OE exhibits a linear behavior within the Ehrenfest time regime, and its slope defines an observable Lyapunov exponent. Using a Pretty Good Measurement correction to the Husimi phase-space distribution, this entropy-production rate quantitatively reproduces the classical Lyapunov exponent in both the standard and singular kicked rotors. Our results establish OE as a compact information-theoretic bridge between classical instability, quantum criticality, and realistic finite-resolution measurements.
format Preprint
id arxiv_https___arxiv_org_abs_2605_23585
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Probing Chaos and Criticality with Observational Entropy and Finite-Resolution Measurements
Kannan, J. Bharathi
PG, Sreeram
Santhanam, M. S.
Quantum Physics
Coarse-grained measurements offer a scalable alternative to full state tomography for characterizing complex quantum dynamics. We show that observational entropy (OE), an information-theoretic entropy defined directly from finite-resolution measurement outcomes, provides a unified and experimentally accessible framework for quantifying chaos and probing criticality. From probing the insulator-metal crossover in the Aubry-Andre model to tracking the gradual destruction of Kolmogorov-Arnold-Moser tori in the Kicked Rotor, derivatives of OE provide an accurate and unified diagnostic of probing these transitions. In both cases, the critical points extracted from dynamical evolution and eigenstate analyses converge to the exact theoretical values once the observational resolution exceeds a finite threshold. In the chaotic limit, OE exhibits a linear behavior within the Ehrenfest time regime, and its slope defines an observable Lyapunov exponent. Using a Pretty Good Measurement correction to the Husimi phase-space distribution, this entropy-production rate quantitatively reproduces the classical Lyapunov exponent in both the standard and singular kicked rotors. Our results establish OE as a compact information-theoretic bridge between classical instability, quantum criticality, and realistic finite-resolution measurements.
title Probing Chaos and Criticality with Observational Entropy and Finite-Resolution Measurements
topic Quantum Physics
url https://arxiv.org/abs/2605.23585