Structure, memory, and rheology in sheared dense suspensions

Recent work [Galloway et al. Nat. Phy. 2022] has uncovered a connection between the structure, memory formation, and rheology of sheared dense suspensions. The relationships found there are demonstrated in bulk and system averaged quantities. Though, as is well known in disordered systems, the microstructure and local dynamics of these systems are strongly heterogeneous. Structural descriptors, like machine-learned softness and local excess entropy, have helped recently in connecting this local, heterogeneous dynamics to the disordered structure. In this work, we explore the connection between the local structural indicators and memory formed in steady state. Between the athermal and supercooled regimes we observe nontrivial behaviour of the steady-state particle dynamics that depends upon the preparation protocol. We connect this to the local structure as represented by excess entropy and softness. These results inform us at a microstructural level how preparation affects the structure, and subsequent memory/dynamics, which leads to distinct rheology.