Flashing subdiffusive ratchets in viscoelastic media
Flashing subdiffusive ratchets in viscoelastic media
复制标题
DOI：
10.1088/1367-2630/14/4/043042
复制
发表时间：
2012-04-27
影响因子：
3.3
通讯作者：
Goychuk, Igor
中科院分区：
文献类型：
--
作者：
Kharchenko, Vasyl;Goychuk, Igor
研究了周期性和随机闪烁电位下的亚扩散棘轮输运。中心布朗粒子与周围辅助布朗准粒子弹性耦合，这解释了粘弹性环境的影响。与布朗运动的标准动力学模型类似，外力只影响中心粒子的运动，而不直接影响环境自由度。只需少量辅助布朗粒子就足以模拟几十年时间内的亚扩散。电势的时间调制违反了热细平衡的对称性，引起了一个反常的亚扩散电流，在低温下表现出非常小的色散，以及许多其他令人惊讶的特征，如低温下的饱和，以及在非绝热状态下驱动频率改变时输运方向的多次反转。结果表明，在零温度下，随机闪蒸的亚扩散电流是有限的，在一定的频率窗内，周期性闪蒸的亚扩散电流是有限的。我们的研究将经典布朗电机推广到在粘性粘弹性环境中运行，如生物细胞的细胞质或密集的聚合物溶液。
We study subdiffusive ratchet transport in periodically and randomly flashing potentials. A central Brownian particle is elastically coupled to the surrounding auxiliary Brownian quasi-particles, which account for the influence of the viscoelastic environment. Similar to standard dynamical modeling of Brownian motion, the external force influences only the motion of the central particle, not affecting directly the environmental degrees of freedom. Just a handful of auxiliary Brownian particles suffices to model subdiffusion over many temporal decades. Time modulation of the potential violates the symmetry of thermal detailed balance and induces an anomalous subdiffusive current which exhibits a remarkably small dispersion at low temperatures, as well as a number of other surprising features such as saturation at low temperatures, and multiple inversions of the transport direction upon a change of the driving frequency in the non-adiabatic regime. It is shown that the subdiffusive current is finite at zero temperature for random flashing and can be finite for periodic flashing for a certain frequency window. Our study generalizes classical Brownian motors towards operating in sticky viscoelastic environments such as the cytosol of biological cells or dense polymer solutions.