Internal mode mechanism for collective energy transport in extended systems

TL;DR

This paper investigates how internal modes enable directed energy transport in nonlinear extended systems, revealing a resonance-based mechanism that determines the direction of motion influenced by initial phases and noise.

Contribution

It introduces a new internal mode mechanism explaining unidirectional motion of topological excitations in nonlinear systems, linking internal and translational degrees of freedom.

Findings

Internal modes couple to translation, enabling directed motion.

Resonance conditions determine the existence and direction of transport.

Motion depends on initial phases and persists despite noise.

Abstract

We study directed energy transport in homogeneous nonlinear extended systems in the presence of homogeneous ac forces and dissipation. We show that the mechanism responsible for unidirectional motion of topological excitations is the coupling of their internal and translation degrees of freedom. Our results lead to a selection rule for the existence of such motion based on resonances that explains earlier symmetry analysis of this phenomenon. The direction of motion is found to depend both on the initial and the relative phases of the two harmonic drivings, even in the presence of noise.