Directed transport of two-coupled particles under the coordination of the coupling and an asymmetric potential.

Directed transport of particles in asymmetric potential fields is an important topic in many scenarios. This article proposes a model to describe the transport of an overdamped system that is composed of two-coupled particles confined by a saw-tooth potential under the Gaussian white noise and driven by a rocking force. The transport of the two-coupled particles exhibits some interesting behaviors, such as the current varies non-monotonically/increase first and then decrease with the coupling strength, there are two inversion points of the transport direction as the free length between the two particles varies, etc. The effective potential defined by adding the asymmetric potential and the coupling between two particles can clearly interpret, based on its overall inclination, the generation of the directed transport in the model. And the direction of movement can be reversed by adjusting the strength of the rocking force and noise under certain ratchet potential. The findings and analysis method allow us to regulate the directed transport of coupled particles via adjusting the combination of the aforementioned factors. • The effective potential is defined by adding the potential and the coupling effect. • The overall tilt of the effective potential is strongly depends on the coupling. • The tilt of the effective potential can interpret the origin of directed transport. • There are two inversion points of the transport direction as the free length varies. • Certain noise intensity and/or rocking force can lead to the current reversal. [ABSTRACT FROM AUTHOR]