Array-induced collective transport in the Brownian motion of coupled nonlinear oscillator systems

TL;DR

This paper investigates how array-induced collective effects influence Brownian motion in coupled nonlinear oscillators, revealing conditions that enhance diffusion or cause phase-locking, with implications for understanding transport in complex systems.

Contribution

It provides an analytical formula for diffusion in single-particle cases and explores the nonlinear response regime where phase-locking affects mobility.

Findings

Coupling can enhance diffusion in the linear response regime.

Phase-locking reduces mobility in the nonlinear regime.

Analytical diffusion rate formula for single particles.

Abstract

Brownian motion of an array of harmonically coupled particles subject to a periodic substrate potential and driven by an external bias is investigated. In the linear response limit (small bias), the coupling between particles may enhance the diffusion process, depending on the competition between the harmonic chain and the substrate potential. An analytical formula of the diffusion rate for the single-particle case is also obtained. In the nonlinear response regime, the moving kink may become phase-locked to its radiated phonon waves, hence the mobility of the chain may decrease as one increases the external force.