The propagation of elastic waves in soft materials plays a crucial role in the spatiotemporal transmission of mechanical signals, e.g., in biological mechanotransduction or in the failure of marginal solids. At high Reynolds numbers Re ≫ 1, inertia dominates and wave propagation is readily observed. However, mechanical cues in soft and biological materials often occur at low Re, where waves are overdamped. Overdamped waves are not only difficult to observe experimentally, also theoretically their description remains incomplete. Here, we present direct measurements of the propagation and attenuation of mechanical signals in colloidal soft solids, induced by an optical trap. We derive an analytical theory for low Re wave propagation and damping, which is in excellent agreement with the experiments. Our results present both a previously unexplored method to characterize damped waves in soft solids and a theoretical framework showing how localized mechanical signals can provoke a remote and delayed response.

弹性波在软质材料中的传播在机械信号的时空传输中起着至关重要的作用，例如在生物机械转导或边缘固体的破坏中。在高雷诺数Re≫ 1时，惯性起主导作用，并且容易观察到波传播。但是，软的和生物的材料中的机械提示通常会在Re较低的情况下发生，在Re处波浪会被过度阻尼。过阻尼波不仅在实验上很难观察到，而且从理论上讲还不完整。在这里，我们介绍由光阱引起的机械信号在胶态软固体中的传播和衰减的直接测量。我们推导出了低Re的分析理论波传播和阻尼，与实验非常吻合。我们的结果既提供了表征软固体中阻尼波的先前未曾探索的方法，又提供了显示局部机械信号如何引起远程响应和延迟响应的理论框架。