Glass does not play dice: Observation of non-random organization of atomic bond tensions in glasses

Self-organization of normal forces under various external stresses (compression, shear) has been extensively studied for granular materials and recently also for liquids and glasses. In order to address this self-organization on an atomic level, we introduced a new parameter, the atomic bond tension (ABT) tensor, that takes into account the magnitudes and the directions associated with "bonds" between an atom and its neighbors. Simulations of four different glassy systems in local equilibrium show that the eigenvalues of ABT tensor belonging to the same atom are correlated on average, favoring local isotropy of normal forces. The strength of these correlations increases with the tendency of the system to be a good glass former.