Drift induced by dissipation

TL;DR

This paper introduces a dissipative particle model where activity emerges from equilibrium fluctuations due to broken gradient structure, highlighting the importance of inertia and proposing a new efficiency measure.

Contribution

It presents a novel dissipative particle model with implicit activity driven by fluctuations, emphasizing the role of inertia and generalizing thermodynamic concepts.

Findings

Activity arises from equilibrium fluctuations without explicit driving.

Inertia critically influences the thermodynamics of active particles.

A simple electric circuit realization demonstrates the model's principles.

Abstract

Active particles have become a subject of intense interest across several disciplines from animal behavior to granular physics. Usually the models of such particles contain an explicit internal driving. Here we propose a model with implicit driving in the sense that the behavior of our particle is fully dissipative at zero temperature but becomes active in the presence of seemingly innocent equilibrium fluctuations. The mechanism of activity is related to the breaking of the gradient structure in the chemo-mechanical coupling. We show that the thermodynamics of such active particles depends crucially on inertia and cannot be correctly captured in the standard Smoluchowski limit. To deal with stall conditions, we generalize the definition of Stokes efficiency, assessing the quality of active force generation. We propose a simple realization of the model in terms of an electric circuit capable of turning fluctuations into a directed current without an explicit source of voltage.