Cutting Self-Similar Space-Filling Sphere Packings

Abstract

Any space-filling packing of spheres can be cut by a plane to obtain a space-filling packing of disks. Here, we deal with space-filling packings generated using inversive geometry leading to exactly selfsimilar fractal packings. First, we prove that cutting along a random hyperplane leads in general to a packing with a fractal dimension of the one of the uncut packing minus one. Second, we find special cuts which can be constructed themselves by inversive geometry. Such special cuts have specific fractal dimensions, which we demonstrate by cutting a three-and a four-dimensional packing. The increase in the number of found special cuts with respect to a cutoff parameter suggests the existence of infinitely many topologies with distinct fractal dimensions.

Frustrated Bearings

“…The concept of bearings plays an important role on the dynamics of dense packings of particles [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]. Bearings obtained by construction that completely fill space [23][24][25][26][27][28] can support large pressures while allowing for sliding movement. Moreover, it was shown that the synchronization process necessary to reach a global bearing state can be substantially enhanced by adjusting the inertial contribution of individual rotors [29].…”