Particle displacements in the elastic deformation of amorphous materials: Local fluctuations vs. non-affine field

We study the local disorder in the deformation of amorphous materials by decomposing the particle displacements into a continuous, inhomogeneous field and the corresponding fluctuations. We compare these fields to the commonly used non- affine displacements in an elastically deformed 2D Lennard- Jones glass. Unlike the non-affine field, the. fluctuations are very localized, and exhibit a much smaller ( and system size independent) correlation length, on the order of a particle diameter, supporting the applicability of the notion of local " defects" to such materials. We propose a scalar " noise". field to characterize the. fluctuations, as an additional. field for extended continuum models, e. g., to describe the localized irreversible events observed during plastic deformation. Copyright (C) EPLA, 2007.