Ratchet motion and current reversal of Brownian motors coupled by birth-death interactions in the crowded environment

Abstract

In this study, we investigate the ratchet transport behaviors of coupled Brownian motors with stochastic interactions in the crowded environment, which is characterized by two parameters, including particle concentration and interacting stability. Thus stationary birth-death process is employed to describe the process of fluctuating particles in the coupled system, and it is a more realistic and accurate description than the conventional variable-mass systems on stochastic phenomena of absorbing and desorbing particles in some complex mediums. It is found that the stochastic interactions could induce the normal or reversal current by influencing the asymmetry and barrier height of effective ratchet potential, and in strong-coupling regime, the dynamical mechanism could be well interpreted. By the numerical simulations, we systematically study the dependence of directed current, stochastic resonance (SR) and coherent resonance (CR) behaviors of transport velocity on various parameters, including particle concentration, interacting stability, coupling strength, spring’s free length, driving amplitude, ratchet asymmetry, and medium temperature. The results also provide the latent support for manipulating transport behaviors and optimizing the coupled structure in artificial nanomachines.