Many macroscopic active systems such as snakes, birds and fishes have flexible shapes and inertial effects on their motion, in contrast to their microscopic counterparts, cannot be ignored. Nonetheless, the consequences of interplay between inertia and flexibility on their shapes and dynamics remain unexplored. Here, we examine inertial effects on the most studied active flexible system, {\it i.e.} linear active filaments pertinent to worms, snakes and filamentous robots. Performing Langevin dynamics simulations of active polymers with underdamped and overdamped dynamics for a wide range of contour lengths and activities, we uncover striking inertial effects on their conformation and dynamics. Inertial collisions increase the persistence length of active polymers and remarkably alter their scaling behavior. In stark contrast to passive polymers, inertia leaves its fingerprint at long times by an enhanced diffusion of the center of mass. We rationalize inertia-induced enhanced dynamics by analytical calculations of center of mass velocity correlations, revealing significant contributions from active force fluctuations convoluted by inertial relaxation.

中文翻译：

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惯性对活性丝构象和动力学的影响

与微观对应物相比，许多宏观活动系统（如蛇、鸟和鱼）具有灵活的形状和对其运动的惯性影响，这是不容忽视的。尽管如此，惯性和灵活性之间相互作用对其形状和动力学的影响仍未得到探索。在这里，我们研究了对研究最多的主动柔性系统的惯性效应，{\it ie} 与蠕虫、蛇和丝状机器人相关的线性主动细丝。针对各种轮廓长度和活动，对具有欠阻尼和过阻尼动力学的活性聚合物进行朗之万动力学模拟，我们发现了对其构象和动力学的惊人惯性效应。惯性碰撞增加了活性聚合物的持久长度并显着改变了它们的缩放行为。与被动聚合物形成鲜明对比的是，由于质心的扩散增强，惯性会在很长一段时间内留下它的印记。我们通过对质心速度相关性的分析计算来合理化惯性引起的增强动力学，揭示由惯性松弛卷积的主动力波动的显着贡献。