Paradoxical non-linear response of a Brownian particle

TL;DR

This paper investigates a Brownian particle in a periodically varying temperature environment, revealing that while linear response remains equilibrium-like, the non-linear response exhibits counterintuitive slowing and reverse movement.

Contribution

It uncovers the paradoxical non-linear response of a Brownian particle under time-dependent temperature variations, highlighting unexpected behavior contrary to equilibrium intuition.

Findings

Linear response matches equilibrium predictions

Non-linear response shows slowing down and reverse motion

Temperature fluctuations induce non-trivial particle dynamics

Abstract

We consider a Brownian particle in a ``meandering'' periodic potential when the ambient temperature is a periodically or stochastically varying function of time. Though far from equilibrium, the linear response of the particle to an external static force is exactly the same as in the equilibrium case, i.e. for constant temperature. Even more surprising is the non-linear response: the particle slows down and then even starts to move in the direction opposite to the applied force.