Probing Dynamical Sensitivity of a Non-KAM System Through Out-of-Time-Order Correlators

Fuente: arXiv
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Auteurs principaux: Varikuti, Naga Dileep, Sahu, Abinash, Lakshminarayan, Arul, Madhok, Vaibhav
Format: Preprint
Publié: 2023
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author Varikuti, Naga Dileep
Sahu, Abinash
Lakshminarayan, Arul
Madhok, Vaibhav
author_facet Varikuti, Naga Dileep
Sahu, Abinash
Lakshminarayan, Arul
Madhok, Vaibhav
contents Non-KAM (Kolmogorov-Arnold-Moser) systems, when perturbed by weak time-dependent fields, offer a fast route to classical chaos through an abrupt breaking of invariant phase space tori. In this work, we employ out-of-time-order correlators (OTOCs) to study the dynamical sensitivity of a perturbed non-KAM system in the quantum limit as the parameter that characterizes the $\textit{resonance}$ condition is slowly varied. For this purpose, we consider a quantized kicked harmonic oscillator (KHO) model, which displays stochastic webs resembling Arnold's diffusion that facilitate large-scale diffusion in the phase space. Although the Lyapunov exponent of the KHO at resonances remains close to zero in the weak perturbative regime, making the system weakly chaotic in the conventional sense, the classical phase space undergoes significant structural changes. Motivated by this, we study the OTOCs when the system is in resonance and contrast the results with the non-resonant case. At resonances, we observe that the long-time dynamics of the OTOCs are sensitive to these structural changes, where they grow quadratically as opposed to linear or stagnant growth at non-resonances. On the other hand, our findings suggest that the short-time dynamics remain relatively more stable and show the exponential growth found in the literature for unstable fixed points. The numerical results are backed by analytical expressions derived for a few special cases. We will then extend our findings concerning the non-resonant cases to a broad class of near-integrable KAM systems.
format Preprint
id arxiv_https___arxiv_org_abs_2306_04209
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Probing Dynamical Sensitivity of a Non-KAM System Through Out-of-Time-Order Correlators
Varikuti, Naga Dileep
Sahu, Abinash
Lakshminarayan, Arul
Madhok, Vaibhav
Chaotic Dynamics
Quantum Physics
Non-KAM (Kolmogorov-Arnold-Moser) systems, when perturbed by weak time-dependent fields, offer a fast route to classical chaos through an abrupt breaking of invariant phase space tori. In this work, we employ out-of-time-order correlators (OTOCs) to study the dynamical sensitivity of a perturbed non-KAM system in the quantum limit as the parameter that characterizes the $\textit{resonance}$ condition is slowly varied. For this purpose, we consider a quantized kicked harmonic oscillator (KHO) model, which displays stochastic webs resembling Arnold's diffusion that facilitate large-scale diffusion in the phase space. Although the Lyapunov exponent of the KHO at resonances remains close to zero in the weak perturbative regime, making the system weakly chaotic in the conventional sense, the classical phase space undergoes significant structural changes. Motivated by this, we study the OTOCs when the system is in resonance and contrast the results with the non-resonant case. At resonances, we observe that the long-time dynamics of the OTOCs are sensitive to these structural changes, where they grow quadratically as opposed to linear or stagnant growth at non-resonances. On the other hand, our findings suggest that the short-time dynamics remain relatively more stable and show the exponential growth found in the literature for unstable fixed points. The numerical results are backed by analytical expressions derived for a few special cases. We will then extend our findings concerning the non-resonant cases to a broad class of near-integrable KAM systems.
title Probing Dynamical Sensitivity of a Non-KAM System Through Out-of-Time-Order Correlators
topic Chaotic Dynamics
Quantum Physics
url https://arxiv.org/abs/2306.04209