arXiv subjects

Itamar Shitrit

Publications and source records attributed to Itamar Shitrit.

3 recordsLinked to original sources

arXiv2026

Pushing-Induced Arrest Across Lattices and Dimensions

Tracer-media interactions can give rise to transport phenomena beyond classical models; e.g., obstacle pushing can eliminate percolation. We demonstrate that the existing "snowplow" mechanism proposed to explain this effect fails in 3D. We show that confinement is governed by emergent trapping-rare "door-closing" events that occur with an approximately constant probability per step at low obstacle densities, thus yielding exponential survival. This allows prediction of the time-dependent mean-squared displacement from short-time estimates of the diffusion constant and trapping probability, providing a minimal description of pushing-induced arrest across lattices and dimensions.

cond-mat.stat-mech↗

arXiv2026

Pushy Random Walk: A Minimal Model for Transport in Deformable Media

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 provides a minimal model for experimentally observed interactions of active particles with dense, deformable media. Using scaling arguments and numerical simulations, we show that in one dimension the walker carves out an obstacle-free cavity whose length grows subdiffusively with 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. These results show how tracer-induced rearrangements qualitatively reshape transport in crowded media.

cond-mat.stat-mech↗

arXiv2024

Sokoban percolation on the Bethe lattice

`With persistence, a drop of water hollows out the stone' goes the ancient Greek proverb. Yet, canonical percolation models do not account for interactions between a moving tracer and its environment. Recently, we have introduced the Sokoban model, which differs from this convention by allowing a tracer to push single obstacles that block its path. To test how this newfound ability affects percolation, we hereby consider a Bethe lattice on which obstacles are scattered randomly and ask for the probability that the Sokoban percolates through this lattice, i.e., escapes to infinity. We present an exact solution to this problem and determine the escape probability as a function of obstacle density. Similar to regular percolation, we show that the escape probability undergoes a second-order phase transition. We exactly determine the critical obstacle density at which this transition occurs and show that it is higher than that of a tracer without obstacle-pushing abilities. Our findings assert that pushing facilitates percolation on the Bethe lattice, as intuitively expected. This result, however, sharply contrasts with our previous findings on the 2D square lattice. There, the Sokoban cannot escape $\unicode{x2013}$ not even at densities well below the percolation threshold. We discuss the reasons behind this striking difference, which calls for a deeper and better understanding of percolation in the presence of tracer-media interactions.

cond-mat.stat-mech↗