Hyperuniformity and conservation laws in non-equilibrium systems

We demonstrate that hyperuniformity, the suppression of density fluctuations at large length scales, emerges generically from the interplay between conservation laws and non-equilibrium driving. The underlying mechanism for this emergence is analogous to self-organized criticality. Based on this understanding, we introduce four non-equilibrium models that consistently demonstrate hyperuniformity. Furthermore, we show that systems with an arbitrary number of conserved mass multipole moments exhibit an arbitrary strong tunable hyperuniform scaling, with the structure factor following $S(k) \sim k^m$, where $m$ is set by the number of conserved multipoles. Finally, we find that hyperuniformity arising from a combination of conserved noise and partially conserved average motion is not robust against non-linear perturbations. Notably, non-linear damping destroys hyperuniformity in hyperuniform fluids. These results highlight the central role of conservation laws in stabilizing hyperuniformity and reveal a unifying mechanism for its emergence in non-equilibrium systems.