The influence of a phase shift between the top and bottom walls on the Brownian transport of self-propelled particles.

Transport of noninteracting self-propelled particles is numerically investigated in a two-dimensional horizontally asymmetrical channel with nonstraight midline which can be controlled by the phase shift between the top and bottom walls. From numerical simulations, we found that self-propelled particles can be rectified by the self-propelled velocity. The direction of the average velocity is determined by the horizontally asymmetrical parameter of the channel. The average velocity is very sensitive to the phase shift and its behaviors can be manipulated by changing the phase shift. As the phase shift is increased, the average velocity decreases and its peak position moves (to right or left). Remarkably, the average velocity is zero when the phase shift is in the interval [ 3π/5, 4π/5 ]. The small phase shift may facilitate the rectification process for the large horizontal asymmetry of the channel. [ABSTRACT FROM AUTHOR]