Distinctive features arising in maximally random jammed packings of superballs

摘要: Dense random packings of hard particles are useful models granular media and closely related to the structure nonequilibrium low-temperature amorphous phases matter. Most work has been done for jammed spheres it is only recently that corresponding nonspherical e.g., ellipsoids have received attention. Here we report a study maximally MRJ binary superdisks monodispersed superballs whose shapes defined by x1 2p + ¯ +xd 1 with d=2 3, respectively, where p deformation parameter values in interval 0, .A sp increases from zero, one can get family both concave 0p0.5 convex p0.5 square symmetry d=2, or octahedral cubic d=3. In particular, p=1 particle perfect sphere circular disk → cube square. We find densities such increase dramatically nonanalytically as moves away circular-disk point p=1. Moreover, disordered hypostatic, i.e., average number contacting neighbors less than twice total degrees freedom per particle, yet mechanically stable. As result, local arrangements necessarily nontrivially correlated achieve jamming. term structures “nongeneric.” The degree “nongenericity” quantitatively characterized determining fraction coordination which central fewer average. also show seemingly “special” packing configurations counterintuitively not rare. anisotropy increases, rattlers decreases while minimal orientational order measured tetratic cubatic parameters increases. These characteristics result unique manner break their rotational symmetry, makes superdisk superball distinctly different other known hard-particle packings.