| Abstract: | Systems with short-range interactions show sqrt(N) fluctuations in equilibrium, except near a critical point, where the fluctuations diverge, with different scaling. We study a class of non-equilibrium systems with a continuous phase transition separating an "absorbing" phase (where the dynamics ultimately ceases) from an "active" phase (where diffusive-like dynamics persists forever). Remarkably even though the interactions are finite ranged, the dynamics lead to a "hyperuniform" state with diminished density fluctuations at the critical point. This prediction can be tested experimentally using a system of sheared colloids. In addition, we derive a scaling relation that relates the anomalous density fluctuations to other known exponents and study the effect of infinitesimal diffusion. |
