Hyperuniformity near jamming transition over a wide range of bidispersity

We numerically investigate hyperuniformity in two-dimensional jammed packings of frictionless bidisperse particles. Hyperuniformity is characterized by the suppression of density fluctuations at large length scales, and the structure factor vanishes at small wave numbers as S(q)∝q^{α}, where α>0. Jammed packings are known to exhibit hyperuniformity over a wide-wave-number window, down to q^{*}σ≈0.2, where σ is the particle diameter. In two dimensions, we find that the exponent α is approximately 0.6-0.7, in contrast to the reported value α=1 in three-dimensional systems. We then extend the analysis to a wide range of particle size ratios, from the monodisperse limit to highly disparate mixtures. To reduce unwanted spatial heterogeneities associated with polycrystalline domains at very large or very small size disparities, we employ a recently proposed method by Rissone et al. [Phys. Rev. Lett. 127, 038001 (2021)10.1103/PhysRevLett.127.038001]. This method enables a more precise determination of α. We find that α remains nearly constant over the entire range of size ratios, except in the monodisperse case, where crystallization occurs.