Quantifying mechanical disorder in computer glasses

In principle, any liquid can form a glass, and different types of glasses can be produced based on the liquid used. Common examples in daily life include polymeric, silica-based, and metallic alloy glasses used in PVC tubes, window panels, and electronic devices. While chemical composition affects certain properties, universal behaviour is observed in glasses. Additionally, their preparation history influences glasses' properties, including factors like cooling rate. This thesis investigates the impact of preparation protocols and inter-particle interactions on the mechanical properties of glasses or amorphous solids.
Amorphous solids exhibit isotropic elastic behaviour at long wavelengths but deviate from continuum mechanics at shorter wavelengths due to particle-scale disorder. Within these disordered structures, glasses contain local environments where small groups of particles can vibrate at unusually low frequencies and energy costs. These excitations, called "soft quasilocalized excitations", influence various thermodynamic, mechanical, transport, and yielding phenomena.
The research presented in this thesis aims to establish the extent of universality in glasses and comprehend how preparation protocols and interparticle interactions affect macro- and microscopic mechanical properties. This is achieved through computer simulations of simplified model systems. The results of this research fall into three main categories: (1) the study of statistical and mechanical properties of soft quasilocalized excitations; (2) understanding the dependence of mechanical properties on the preparation process and interparticle interactions; and (3) quantifying the variability of mechanical fluctuations resulting from different preparation protocols in a broad range of computer-generated glasses.