Forcing inertial Brownian motors: efficiency and negative differential mobility

TL;DR

This paper investigates the behavior of inertial Brownian motors under external bias, revealing non-monotonic velocity-load relationships with negative differential mobility and comparing various efficiency measures from different physical viewpoints.

Contribution

It demonstrates the existence of negative differential mobility in inertial Brownian motors and compares multiple efficiency quantifiers to understand their physical implications.

Findings

Velocity-load characteristics are non-monotonic.

Regimes with negative differential mobility are identified.

Different efficiency quantifiers are evaluated and compared.

Abstract

The noise-assisted, directed transport in a one-dimensional dissipative, inertial Brownian motor of the rocking type that is exposed to an external bias is investigated. We demonstrate that the velocity-load characteristics is distinctly non-monotonic, possessing regimes with a {\em negative differential mobility}. In addition, we evaluate several possible efficiency quantifiers which are compared among each other. These quantifiers characterize the mutual interplay between the viscous drag and the external load differently, weighing the inherent rectification features from different physical perspectives.