title: Energy transport in jammed sphere packings.
abstract: We calculate the normal modes of vibration in jammed sphere packings to obtain the energy diffusivity, a spectral measure of transport. At the boson peak frequency, we find an Ioffe-Regel crossover from a diffusivity that drops rapidly with frequency to one that is nearly frequency independent. This crossover frequency shifts to zero as the system is decompressed towards the jamming transition, providing unambiguous evidence of a regime in frequency of nearly constant diffusivity. Such a regime, postulated to exist in glasses to explain the temperature dependence of the thermal conductivity, therefore appears to arise from properties of the jamming transition.
authors.affiliation: Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
authors.forename: Ning
authors.initials: N
authors.lastname: Xu
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Vitelli
authors.forename: Matthieu
authors.initials: M
authors.lastname: Wyart
authors.forename: Andrea J
authors.initials: AJ
authors.lastname: Liu
authors.forename: Sidney R
authors.initials: SR
authors.lastname: Nagel