Elasticity of self-organized frustrated disordered spring networks

Abstract

There have been some interesting recent advances in understanding the notion of mechanical disorder in structural glasses and the statistical mechanics of these systems' low-energy excitations. Here we contribute to these advances by studying a minimal model for structural glasses' elasticity in which the degree of mechanical disorder -- as characterized by recently introduced dimensionless quantifiers -- is readily tunable over a very large range. We comprehensively investigate a number of scaling laws observed for various macro-, meso- and microscopic elastic properties, and rationalize them using scaling arguments. Interestingly, we demonstrate that the model features the universal quartic glassy vibrational density of states as seen in many atomistic and molecular models of structural glasses formed by cooling a melt. The emergence of this universal glassy spectrum highlights the role of self-organization (towards mechanical equilibrium) in its formation, and elucidates why models featuring structural frustration alone do not feature the same universal glassy spectrum. Finally, we discuss relations to existing work in the context of strain-stiffening of elastic networks and of low-energy excitations in structural glasses, in addition to future research directions.