Dynamical time scales of friction dynamics in active microrheology of a model glass

Owing to the local/heterogeneous structures in supercooled liquids, after several decades of research, it is now clear that supercooled liquids are structurally different from their conventional liquid counterparts. Accordingly, an approach based on a local probe should provide a better understanding about the local mechanical properties as well as heterogeneous structures. Recently, the superiority of active microrheology over global rheology has been demonstrated [Yu et al., Sci. Adv., 2020, 6, 8766]. Here, we elaborate this new avenue of research and provide more evidence for such superiority. We report on the results of an extensive molecular dynamics simulation of active microrheology of a model glass. We identify several time scales in time series of friction, and detect a transition in dynamical behavior of friction. We discuss the possible relation to structural heterogeneities-a subject of considerable interest in glass physics.

Automated summary

Research has shown that supercooled liquids have structurally different properties from conventional liquids, and using active microrheology based on a local probe can provide a better understanding of local mechanical properties and heterogeneous structures. Through extensive molecular dynamics simulations, it has been identified that there are multiple time scales in the friction time series, and a transition in the dynamical behavior of friction has been detected, possibly related to structural heterogeneities.