含时摩擦系数和扩散调控布朗粒子的异常输运

Tunable anomalous transports of Brownian particle via time-dependent friction coefficient and diffusion

研究空间周期对称系统中惯性布朗粒子在热涨落和时间周期力的驱动下的输运问题.首先,建立由涨落产生的惯性布朗粒子模型,并给出数值计算方法.结果发现:随着初始扩散系数的增大,棘轮效应在增强.然而随着温度衰减的时间特征的增大,棘轮效应在减弱;当扩散的幂律指数较小时,有棘轮效应出现,但是当扩散的幂律指数较大时,棘轮效应消失,然而当扩散的幂律指数更大时,有负迁移现象出现;不同的初始扩散系数、温度衰减的时间特征、扩散的幂律指数对应于不同的扩散.发现可用于粒子的分类、癌细胞的分离、分子马达的控制.

We numerically investigate the anomalous transports of an inertial Brownian particle moving in a spatial-periodic symmetric system with a time-dependence of the system temperature,diffusion coefficient and damping coefficient.The results manifest as follows.The initial diffusion coefficient can enhance the ratchet effect.However,the characteristic time of the temperature decay can weaken the ratchet effect.The ratchet effect can occur at the small power-law exponent of diffusion and vanish at the large power-law exponent of diffusion.What’s more,the negative mobility can occur at the larger power-law exponent of diffusion.Different initial diffusion coefficients,characteristic times of the temperature decay,and power-law exponents of diffusion correspond to different diffusions.Our findings may be applied to the separation of particles,cancer cells,and control of molecular motors.