Diffusion/Subdiffusion in the Pushy Random Walk

Abstract: We introduce the pushy random walk, where a walker can push multiple obstacles, thereby penetrating large distances in environments with finite obstacle density. This process gives a more realistic depiction of experimentally observed interactions of active particles in dense media. In one dimension, the walker carves out an obstacle-free cavity whose length grows subdiffusively over time. In two dimensions, increasing obstacle density drives a transition from free diffusion to localized behavior, where the walker is trapped within a cavity whose radius again grows subdiffusively with time.