Abstract

Experiments of periodically sheared colloidal suspensions or soft amorphous solids display a transition from reversible to irreversible particle motion that, when analysed stroboscopically in time, is interpreted as an absorbing phase transition with infinitely many absorbing states. This was widely considered to belong to the Conserved Directed Percolation (CDP) universality class, at which the system displays very weak density fluctuations (hyper-uniformity).

In these systems, however, interactions mediated by hydrodynamics or elasticity are present, causing passive regions to be affected by active ones. I will introduce and discuss a minimal model for for the stroboscopic dynamics of sheared soft materials, designed to include the effect of mediated interactions. I will show that they induce a new universality class, distinct from CDP . These results are obtained by a combination of numerical simulations and by a mean-field analysis that allows to derive the field theoretical description of the absorbing phase transition.