Lyapunov Mode Dynamics in Hard-Disk Systems

TL;DR

This paper investigates the dynamics of Lyapunov modes in hard-disk systems, proposing a new phenomenological model that accurately describes their linear and time-invariant behavior, supported by numerical tests.

Contribution

It introduces a novel phenomenological description of Lyapunov mode dynamics and a detailed structure for their tangent dynamics, highlighting their stability properties.

Findings

Lyapunov mode dynamics are linear and separate from other tangent space components.

The phenomenological model reproduces experimental data for quasi-one-dimensional systems.

Numerical tests show partial success in validating the proposed tangent dynamics.

Abstract

The tangent dynamics of the Lyapunov modes and their dynamics as generated numerically - {\it the numerical dynamics} - is considered. We present a new phenomenological description of the numerical dynamical structure that accurately reproduces the experimental data for the quasi-one-dimensional hard-disk system, and shows that the Lyapunov mode numerical dynamics is linear and separate from the rest of the tangent space. Moreover, we propose a new, detailed structure for the Lyapunov mode tangent dynamics, which implies that the Lyapunov modes have well-defined (in)stability in either direction of time. We test this tangent dynamics and its derivative properties numerically with partial success. The phenomenological description involves a time-modal linear combination of all other Lyapunov modes on the same polarization branch and our proposed Lyapunov mode tangent dynamics is based upon the form of the tangent dynamics for the zero modes.