  We explore the quantum dynamics of a one-dimensional trapped ultracold
ensemble of bosonic atoms triggered by the sudden creation of a single ion. The
numerical simulations are performed by means of the ab initio
multiconfiguration time-dependent Hartree method for bosons which takes into
account all correlations. The dynamics is analyzed via a cluster expansion
approach, adapted to bosonic systems of fixed particle number, which provides a
comprehensive understanding of the occurring many-body processes. After a
transient during which the atomic ensemble separates into fractions which are
unbound and bound with respect to the ion, we observe an oscillation in the
atomic density which we attribute to the additional length and energy scale
induced by the attractive long-range atom-ion interaction. This oscillation is
shown to be the main source of spatial coherence and population transfer
between the bound and the unbound atomic fraction. Moreover, the dynamics
exhibits collapse and revival behavior caused by the dynamical build-up of
two-particle correlations demonstrating that a beyond mean-field description is
indispensable.
