Giant coherence in driven systems

TL;DR

This paper investigates noise-induced currents and transport coherence in driven Brownian ratchets, revealing conditions for giant coherence and how it varies with parameters like temperature and driving frequency.

Contribution

It demonstrates the occurrence of giant transport coherence in symmetric ratchet systems and analyzes how coherence depends on driving and temperature regimes.

Findings

Giant coherence occurs in symmetric ratchets with unidirectional currents.

Transport coherence decreases with temperature and varies non-monotonically with driving amplitude.

Reliability of transport diminishes moving from adiabatic to non-adiabatic regimes.

Abstract

We study the noise-induced currents and reliability or coherence of transport in two different classes of rocking ratchets. For this, we consider the motion of Brownian particles in the over damped limit in both adiabatic and non-adiabatic regimes subjected to unbiased temporally symmetric and asymmetric periodic driving force. In the case of a time symmetric driving, we find that even in the presence of a spatially symmetric simple sinusoidal potential, highly coherent transport occurs. These ratchet systems exhibit giant coherence of transport in the regime of parameter space where unidirectional currents in the deterministic case are observed. Outside this parameter range, i.e., when current vanishes in the deterministic regime, coherence in transport is very low. The transport coherence decreases as a function of temperature and is a non-monotonic function of the amplitude of driving. The transport becomes unreliable as we go from the adiabatic to the non-adiabatic domain of operation.