Microscopic Theory for Hyperuniformity in Two-Dimensional Chiral Active Fluids

In this chapter, we develop a microscopic theory of hyperuniformity in two-dimensional chiral active fluids. Starting from a particle-based model, we construct a fluctuating hydrodynamic description in which two parameters, the persistence time and the chiral torque, control the behavior of the system. A linear analysis of the resulting hydrodynamic equations yields an analytical expression for the static structure factor. In the limit of infinite persistence time, the theory predicts hyperuniformity characterized by the same exponent as that observed in numerical simulations. We further perform a qualitative comparison between the theoretical predictions and numerical results for various parameter sets.