title: Experiments on random packings of ellipsoids.
abstract: Recent simulations indicate that ellipsoids can pack randomly more densely than spheres and, remarkably, for axes ratios near 1.25:1:0.8 can approach the densest crystal packing (fcc) of spheres, with a packing fraction of 74%. We demonstrate that such dense packings are realizable. We introduce a novel way of determining packing density for a finite sample that minimizes surface effects. We have fabricated ellipsoids and show that, in a sphere, the radial packing fraction phi(r) can be obtained from V(h), the volume of added fluid to fill the sphere to height h. We also obtain phi(r) from a magnetic resonance imaging scan. The measurements of the overall density phi(avr), phi(r) and the core density phi(0) = 0.74 +/- 0.005 agree with simulations.
authors.affiliation: Department of Physics, Princeton University, New Jersey 08544, USA.
authors.forename: Weining
authors.initials: W
authors.lastname: Man
authors.forename: Aleksandar
authors.initials: A
authors.lastname: Donev
authors.forename: Frank H
authors.initials: FH
authors.lastname: Stillinger
authors.forename: Matthew T
authors.initials: MT
authors.lastname: Sullivan
authors.forename: William B
authors.initials: WB
authors.lastname: Russel
authors.forename: David
authors.initials: D
authors.lastname: Heeger
authors.forename: Souheil
authors.initials: S
authors.lastname: Inati
authors.forename: Salvatore
authors.initials: S
authors.lastname: Torquato
authors.forename: P M
authors.initials: PM
authors.lastname: Chaikin