Transverse rectification of disorder-induced fluctuations in a driven system

TL;DR

This paper investigates how quenched disorder influences the transverse drift of particles in a driven two-dimensional ratchet system, revealing disorder-enhanced rectification linked to an effective temperature concept.

Contribution

It introduces a novel understanding of disorder effects on transverse rectification in geometrical ratchets, connecting it to effective temperature and generalized Einstein relations.

Findings

Disorder can significantly enhance transverse drift at low temperatures.

Transverse velocity response is equivalent to a one-dimensional flashing ratchet at an effective temperature.

Disorder reduces transverse mobility despite increasing rectification.

Abstract

We study numerically the overdamped motion of particles driven in a two dimensional ratchet potential. In the proposed design, of the so-called geometrical-ratchet type, the mean velocity of a single particle in response to a constant force has a transverse component that can be induced by the presence of thermal or other unbiased fluctuations. We find that additional quenched disorder can strongly enhance the transverse drift at low temperatures, in spite of reducing the transverse mobility. We show that, under general conditions, the rectified transverse velocity of a driven particle fluid is equivalent to the response of a one dimensional flashing ratchet working at a drive-dependent effective temperature, defined through generalized Einstein relations.