Chaotic dynamics and spin correlation functions in a chain of nanomagnets

TL;DR

This paper investigates the chaotic dynamics and spin correlation functions in a classical model of a nanomagnet chain, revealing how chaos influences spin correlations and the role of anisotropy.

Contribution

It introduces an effective Hamiltonian approach for a nanomagnet chain and links classical chaos metrics to spin correlation decay.

Findings

Correlation decay depends logarithmically on Lyapunov exponent

Exchange anisotropy significantly affects dynamics

Chaotic behavior influences spin correlation times

Abstract

We study a chain of coupled nanomagnets in a classical approximation. We show that the infinitely long chain of coupled nanomagnets can be equivalently mapped onto an effective one-dimensional Hamiltonian with a fictitious time-dependent perturbation. We establish a connection between the dynamical characteristics of the classical system and spin correlation time. The decay rate for the spin correlation functions turns out to depend logarithmically on the maximal Lyapunov exponent. Furthermore, we discuss the non-trivial role of the exchange anisotropy within the chain.