Directed motion generated by heat bath nonlinearly driven by external noise

TL;DR

This paper introduces a microscopic model where a heat bath modulated by external noise induces directed motion in an overdamped system, highlighting the role of nonlinear bath driving and state-dependent diffusion.

Contribution

It develops a new Langevin and Fokker-Planck framework for systems with a nonlinearly driven heat bath, exploring phase-induced currents and thermodynamic consistency.

Findings

Directed motion can be generated by nonlinear bath modulation.

State-dependent diffusion leads to phase-induced currents.

The model maintains thermodynamic consistency.

Abstract

Based on the system heat bath approach where the bath is nonlinearly modulated by an external Gaussian random force, we propose a new microscopic model to study directed motion in the overdamped limit for a nonequilibrium open system. Making use of the coupling between the heat bath and the external modulation as a small perturbation we construct a Langevin equation with multiplicative noise and space dependent dissipation and the corresponding Fokker-Planck-Smoluchowski equation in the overdamped limit. We examine the thermodynamic consistency condition and explore the possibility of observing a phase induced current as a consequence of state dependent diffusion and, necessarily, nonlinear driving of the heat bath by the external noise.