Energy propagation through dense granular systems

We discuss affine and non-affine components of particle dynamics in the context of energy propagation through dense granular matter as a consequence of externally imposed boundary perturbation. Earlier work (Kondic et al. in Phys Rev E 79:041304, 2009) has shown that the frequency and the wavenumber of the imposed perturbations strongly influence propagation, and in particular that the frequencies and wavenumbers that lead to well-defined propagation are limited from above. The present work shows that strong non-affine component of particle dynamics is associated with dispersion and loss of coherence.