Memory-Induced Transition from a Persistent Random Walk to Circular Motion for Achiral Microswimmers
Memory-Induced Transition from a Persistent Random Walk to Circular Motion for Achiral Microswimmers
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DOI：
10.1103/physrevlett.121.078003
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发表时间：
2018-08-17
影响因子：
8.6
通讯作者：
Ruben Gomez-Solano, Juan
中科院分区：
文献类型：
--
作者：
Narinder, N.;Bechinger, Clemens;Ruben Gomez-Solano, Juan
我们通过实验研究光激活胶体微型游泳器在粘弹性流体中的运动。我们发现，在这样的非牛顿环境中，活性胶体经历了意想不到的转变，从增强的角扩散到高于临界推进速度的持续旋转运动，尽管它们是球形和刚度的。我们观察到，与手性不对称微型游泳器相比，由此产生的圆形轨道可以自发地反转其旋转方向，并表现出与推进速度非线性相关的角速度和曲率半径。通过主动布朗运动的最小非马尔可夫朗之万模型，我们表明这些非平衡效应是由于流体相对于牛顿流体中没有对应物的粒子自推进的延迟响应而出现的。
We experimentally study the motion of light-activated colloidal microswimmers in a viscoelastic fluid. We find that, in such a non-Newtonian environment, the active colloids undergo an unexpected transition from enhanced angular diffusion to persistent rotational motion above a critical propulsion speed, despite their spherical shape and stiffness. We observe that, in contrast to chiral asymmetric microswimmers, the resulting circular orbits can spontaneously reverse their sense of rotation and exhibit an angular velocity and a radius of curvature that nonlinearly depend on the propulsion speed. By means of a minimal non-Markovian Langevin model for active Brownian motion, we show that these nonequilibrium effects emerge from the delayed response of the fluid with respect to the self-propulsion of the particle without counterpart in Newtonian fluids.