Cesare Nardini

Eur. Phys. J. E (2025) 48: 59 https://doi.org/10.1140/epje/s10189-025-00519-x Regular Article - Flowing Matter Random organization criticality with long-range hydrodynamic interactions 1, 2, 1 and 1a 1 Univ.

Abstract Self-propelled particles such as bacteria or algae swimming through a fluid are non-equilibrium systems where particle motility breaks microscopic detailed balance, often resulting in large-scale collective motion. Previous theoretical work has identified long-ranged hydrodynamic interactions as the driver of collective motion in unbounded suspensions of rear-actuated (“pusher”) microswimmers.

Abstract Experiments of periodically sheared colloidal suspensions or soft amorphous solids display a transition from reversible to irreversible particle motion that, when analyzed stroboscopically in time, is interpreted as an absorbing phase transition with infinitely many absorbing states. In these systems, interactions mediated by hydrodynamics or elasticity are present, causing passive regions to be affected by nearby active ones.