  We investigate the dynamics of a homogenous Bose-Einstein condensate (BEC)
following a sudden quench of the scattering length. Our focus is the time
evolution of short-range correlations via the dynamical contact. We compute the
dynamics using a combination of two- and many-body models, and we propose an
intuitive connection between them that unifies their short-time, short-range
predictions. Our two-body models are exactly solvable and, when properly
calibrated, lead to analytic formulae for the contact dynamics. Immediately
after the quench, the contact exhibits strong oscillations at the frequency of
the two-body bound state. These oscillations are large in amplitude, and their
time average is typically much larger than the unregularized Bogoliubov
prediction. The condensate fraction shows similar oscillations, whose amplitude
we are able to estimate. These results demonstrate the importance of including
the bound state in descriptions of diabatically-quenched BEC experiments.
