Transport and diffusion of active Brownian particles in a new asymmetric bistable system driven by two Gaussian colored noises

Abstract

The transport phenomena (drift and diffusion) of active Brownian particles in a new asymmetric bistable system with a linear bias force and a nonlinear bias force subjected to two colored noises are investigated. Two different biases break the symmetry of the potential to generate motion of the particle with a net velocity. Theoretical analysis of the system is given by virtue of the Langevin equation and the Fokker-Planck methods, which is verified by numerical simulation. The results show that: (i) coexistence of the linear bias and nonlinear bias is capable of tuning the transport of the particle, including current reversal, absolute negative mobility, directional transport; (ii) in the absence of linear bias F, the mean velocity is negative for positive nonlinear bias r but positive for negative r, that is, the nonlinear bias leads to absolute negative mobility. In the absence of nonlinear bias r, the mean velocity is positive for positive linear bias F and negative for negative F; (iii) as the absolute values of the linear bias and nonlinear bias increase, the mean velocity is promoted but the effective diffusion is suppressed; (iv) the enhancement of the multiplicative and additive noise intensities can suppress the transport and effective diffusion; and (v) the transport velocity and diffusion are facilitated with increasing the auto-correlation times of two colored noises. Furthermore, the physical mechanism for the particle’s transport is derived from the velocity distributions and the effective velocity potential gap of the above results.