  Flexible Rydberg aggregates, assemblies of few Rydberg atoms coherently
sharing electronic excitations while undergoing directed atomic motion, show
great promise as quantum simulation platform for nuclear motional dynamics in
molecules or quantum energy transport. Here we study additional features that
are enabled by the presence of more than a single electronic excitation, thus
considering multi-exciton states. We describe cases where these can be
decomposed into underlying single exciton states and then present dynamical
scenarios with atomic motion that illustrate exciton-exciton collisions,
exciton routing, and strong non-adiabatic effects in simple one-dimensional
settings.
