  We study a model amorphous solid that is subjected to repeated athermal
cyclic shear deformation. It has previously been demonstrated that the memory
of the amplitudes of shear deformation the system is subjected to (or trained
at) is encoded, and can be retrieved by subsequent deformation cycles that
serve as read operations. Here we consider different read protocols and
measurements and show that single and multiple memories can be robustly
retrieved through these different protocols. We also show that shear
deformation by a larger amplitude always erases the stored memories. These
observations are similar to those in experiments with non-Brownian colloidal
suspensions and corresponding models, but differ in the possibility of storing
multiple memories non-transiently. Such a possibility has been associated with
the presence of cycles of transitions that take place in the model amorphous
solids, between local energy minima. Here, we study low density sphere
assemblies which serve as models for non-Brownian colloidal suspensions, under
athermal deformation, and identify a regime where multiple memories are stored
in these systems as well non-transiently. We show that the regime where storing
multiple memories non-transiently corresponds to the presence of loop
reversibility, rather than point reversibility of configurations under cyclic
deformation.
