Abstract:The transport of Brownian particles moving along a three-dimensional fluctuating tube is investigated in the presence of a load. The tube wall can fluctuate between two states. Coarsening the description of a process for the sake of simplifying the dynamic will result in an entropic barrier and an effective diffusion coefficient. It is found that we can control the asymmetric parameter and the load force to control the current direction and there is an optimized transition rate at which the current takes a maximum value.

We study the transport of overdamped Brownian particles in a symmetrically periodic potential in the presence of an asymmetrically ac driving force and a time-delayed feedback. It is found that for low frequencies, the average velocity can be negative by changing the driving amplitude, for high frequencies, there exists an optimized driving amplitude at which the average velocity takes its maximum value. Additionally, there is a threshold value of driving amplitude below which no directed transport can be obtained for high frequencies. For the large value of the delay time, the average velocity is independent of the delay time.