论文标题
活性列表界面的活性分散
Dispersion of activity at an active-passive nematic interface
论文作者
论文摘要
有效的养分混合对于细菌菌落和其他生活系统的存活至关重要。这就提出了一个问题，即通过细菌群中主动湍流运动的优化是否在细菌形状的进化中起作用。在这里，为了解决这个问题，我们解决了活性nematics的流体动力方程，并为营养素的对流扩散方程式求解。后者模拟了保守的活性场，并模仿细菌群中养分的保存。在活性和被动列之间的界面上，除了扩散外，活性是通过界面流传输的，进而通过主动应力修改它们。我们发现，保守活性的界面分散剂是由于在有源 - 假体接口处出现负缺陷的屏障而延伸的，这阻碍了运动阳性缺陷的传播。此外，我们观察到广义扩散系数对对齐参数的非单调依赖性，这与粒子的形状有关。我们的模拟表明，有一个最佳形状，可以最大程度地提高活性列列界面上保守活动的分散体。
Efficient nutrient mixing is crucial for the survival of bacterial colonies and other living systems. This raises the question of whether the optimization of mixing through the emergence of active turbulent motion in bacterial swarms played a role in the evolution of bacterial shapes. Here, to address this question, we solve the hydrodynamic equation for active nematics coupled with an advection-diffusion equation for the nutrients. The latter models a conserved activity field and mimics the conservation of nutrients in bacterial swarms. At the interface between active and passive nematic phases, in addition to diffusion, the activity is transported by interfacial flows and in turn modifies them through active stresses. We find that the interfacial dispersion of the conserved activity is subdiffusive due to the emergence of a barrier of negative defects at the active-passive interface, which hinders the propagation of the motile positive defects. Furthermore, we observe a non-monotonic dependence of the generalized diffusion coefficient on the aligning parameter, which is related to the shape of the particles. Our simulations suggest that there is an optimal shape that maximizes the dispersion of conserved activity at the active-passive nematic interface.
