State-dependent driving: A route to non-equilibrium stationary states

TL;DR

This paper investigates how state-dependent driving in frictional systems can lead to non-equilibrium stationary states, combining experiments and a minimal model to explain the emergence of complex stationary behaviors.

Contribution

It introduces a minimalistic phenomenological model that captures the effects of state-dependent energy injection on frictional systems, supported by experimental evidence.

Findings

Emergence of non-trivial stationary states in frictional systems

State-dependent driving causes repeated toggling of frictional states

Model successfully explains experimental observations

Abstract

We study three different experiments that involve dry friction and periodic driving, and which employ both single and many-particle systems. These experimental set-ups, besides providing a playground for investigation of frictional effects, are relevant in broad areas of science and engineering. Across all these experiments, we monitor the dynamics of objects placed on a substrate that is being moved in a horizontal manner. The driving couples to the degrees of freedom of the substrate, and this coupling in turn influences the motion of the objects. Our experimental findings suggest emergence of stationary-states with non-trivial features. We invoke a minimalistic phenomenological model to explain our experimental findings. Within our model, we treat the injection of energy into the system to be dependent on its dynamical state, whereby energy injection is allowed only when the system is in its suitable-friction state. Our phenomenological model is built on the fact that such a state-dependent driving results in a force that repeatedly toggles the frictional states in time, and serves to explain our experimental findings.