Fractional Brownian motors and Stochastic Resonance

TL;DR

This paper investigates fractional Brownian motors in viscoelastic media, revealing how anomalous diffusion affects rectification, stochastic resonance, and transport properties, with implications for understanding subdiffusive ratchets.

Contribution

It introduces a model of fractional Brownian ratchets in viscoelastic media, analyzing how anomalous diffusion influences rectification and stochastic resonance effects.

Findings

Rectification vanishes in slow modulation limit

Optimal frequency and temperature maximize stochastic resonance

Subdiffusive current can reverse direction with parameter changes

Abstract

We study fluctuating tilt Brownian ratchets based on fractional subdiffusion in sticky viscoelastic media characterized by a power law memory kernel. Unlike the normal diffusion case the rectification effect vanishes in the adiabatically slow modulation limit and optimizes in a driving frequency range. It is shown also that anomalous rectification effect is maximal (stochastic resonance effect) at optimal temperature and can exhibit a surprisingly good quality. Moreover, subdiffusive current can flow in the counter-intuitive direction upon a change of temperature or driving frequency. The dependence of anomalous transport on load exhibits a remarkably simple universality.