Density fluctuations (A) and structure factor (B) for an ensemble of simulated active Langevin circle swimmers. The particles are of diameter σ and interact via excluded volume interactions. The radius of the circular trajectory is R. The system exhibits a R-dependent length scale that controls the hyperuniform behaviour. On length scales r≪R, the particles move effectively straight and behave like an active gas, while for r≫R, the particles exhibit a chiral trajectory and the hyperhuniform behaviour can be observed. Reprinted with permission from [146]. Copyright©2019 The Author(s).