Worm tunneling across entropic barriers in granular media*

We will discuss the dynamics of limbless California blackworms in heterogenous media using model quasi-2D pores separated by a narrow channel. These aquatic worms are known to move using dual undulatory and peristaltic strokes [1]. Tracking the worms as they move across the entropic barrier presented by the channels due their large aspect ratios, we obtain the center of mass and high moments of the mass distribution within the system over long periods. The worms are observed to translocate with increasing probability with decreasing channel length and width. We will discuss the residence time \tau_r and transition time \tau_t as a function of the ratio of the channel to worm width, and the ratio of the worm length to channel length. Comparison will be presented of this active matter system versus thermally activated systems.  The effect of applied fields and entanglements will be further discussed.    

 

[1]: A. Kudrolli and B. Ramirez, PNAS 116, 25569 (2019).