  Some aspects of how sound waves travel through disordered solids are still
unclear. Recent work has characterized a feature of disordered solids which
seems to influence vibrational excitations at the mesoscales, local elastic
heterogeneity. Sound waves propagation has been demonstrated to be strongly
affected by inhomogeneous mechanical features of the materials which add to the
standard anharmonic couplings, amounting to extremely complex transport
properties at finite temperatures. Here, we address these issues for the case
of a simple atomic glass former, by Molecular Dynamics computer simulation. In
particular, we focus on the transverse components of the vibrational
excitations in terms of dynamic structure factors, and characterize the
temperature dependence of sound dispersion and attenuation in an extended
frequency range. We provide a complete picture of how elastic heterogeneity
determines transport of vibrational excitations, also based on a direct
comparison of the numerical data with the predictions of the heterogeneous
elastic theory.
