Scattering of elastic waves in amorphous solids: revisiting the long wavelength limit Simon Gelin, département de physique, UdeMchercheur postdoctoral (groupe de Normand Mousseau)

abstract:

When excited in amorphous solids (fused silica for instance), mechanical waves are damped out by various mechanisms which, depending on the solid temperature and the wave frequency, may include atomic tunneling, elastic scattering by structural disorder or anharmonic phonon coupling. The scattering by structural disorder in the large wavelength limit is particularly interesting because it is controlled by local heterogeneities in the solid and might thus give information about their properties. As an example, if fluctuations of local elasticity were to rapidly decorrelate in space, as was expected so far, the damping coefficient would obey the Rayleigh law. Relying on new results obtained in a two-dimensional numerical model of glass as well as numerical and experimental data available in the literature, this presentation will first show that the damping coefficient quite surprisingly deviates logarithmically from the Rayleigh law in amorphous solids. Then it will be evidenced that this deviation originates from long range correlations of elastic disorder which are themselves a consequence of similar stress correlations.

Cette conférence est présentée par le RQMPVersant Nord du Département de physiquede l'Université de Montréal et de Génie physique de la Polytechnique.