  We consider the general problem of quenching an interacting Bose gas from the
noninteracting regime to the strong repulsive case described by the
Tonks-Girardeau limit, with the initial state being a gaussian ensemble for the
bosons. A generic multi-point correlation function in the steady state can be
fully described in terms of a Fredholm-like determinant suitable both for a
numerical study and for an analytical study in certain limiting cases. Finally,
we extend the study to the presence of a smooth confining potential showing
that, in the thermodynamic limit, the time evolution of the two-point function
can be mapped to a classical problem in a properly defined phase-space.
