Speed-Fisher Information: Chaos and Irreversibility in Classical and Quantum Dynamics

arXiv:2609.35687 · cond-mat.stat-mech, nlin.CD, quant-ph · Submitted 2026-09-28 · Read on arXiv

cond-mat.stat-mech, nlin.CD, quant-ph

Submitted: 2026-09-28

Updated: 2026-09-28

Comments: 23 pages, 10 figures

License: http://creativecommons.org/licenses/by/4.0/

The gist: We propose a unified perspective on classical and quantum chaos based on the sensitivity of a system's stationary states to slow driving.

Terminology

Abstract

We propose a unified perspective on classical and quantum chaos based on the sensitivity of a system's stationary states to slow driving. We probe this sensitivity via the system's susceptibility to the average protocol speed, which we call the ``speed-Fisher information," and relate it to irreversible entropy production in the system. We show that chaotic dynamics manifests as a divergence of the speed-Fisher information with the protocol time, and that this response is controlled by the perturbation's low-frequency spectral weight. This approach to chaos applies to both classical and quantum Hamiltonian systems, and naturally extends to non-Hamiltonian classical flows. Additionally, we identify a quantum regime at times shorter than the Planckian timescale, in which the speed-Fisher information exhibits a uniquely quantum scaling. We illustrate this framework with simple classical and quantum examples

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