2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/123155We study the dynamics of shock-tracking probe particles in driven diffusive systems and also in equilibrium systems. In a driven system, they induce a diverging timescale that marks the crossover between a passive scalar regime at early times and a diffusive regime at late times; a scaling form characterises this crossover. Introduction of probes into an equilibrium system gives rise to a system-wide density gradient, and the presence of even a single probe can be felt across the entire system.Accepted in Journal of Statistical Mechanics: Theory and ExperimentStatistical Mechanicstext