  Disordered hyperuniform structures are an exotic state of matter having
vanishing long-wavelength density fluctuations similar to perfect crystals but
without long-range order. Although its importance in materials science has been
brought to the fore in past decades, the rational design of experimentally
realizable disordered strongly hyperuniform microstructures remains
challenging. Here we find a new type of non-equilibrium fluid with strong
hyperuniformity in two-dimensional systems of chiral active particles, where
particles perform independent circular motions of the radius R with the same
handedness. This new hyperuniform fluid features a special length scale, i.e.,
the diameter of the circular trajectory of particles, below which large density
fluctuations are observed. By developing a dynamic mean-field theory, we show
that the large local density fluctuations can be explained as a
motility-induced microphase separation, while the Fickian diffusion at large
length scales and local center-of-mass-conserved noises are responsible for the
global hyperuniformity.
