  Fractonic constraints can lead to exotic properties of quantum many-body
systems. Here, we investigate the dynamics of fracton excitations on top of the
ground states of a one-dimensional, dipole-conserving Bose-Hubbard model. We
show that nearby fractons undergo a collective motion mediated by exchanging
virtual dipole excitations, which provides a powerful dynamical tool to
characterize the underlying ground state phases. We find that in the gapped
Mott insulating phase, fractons are confined to each other as motion requires
the exchange of massive dipoles. When crossing the phase transition into a
gapless Luttinger liquid of dipoles, fractons deconfine. Their transient
deconfinement dynamics scales diffusively and exhibits strong but subleading
contributions described by a quantum Lifshitz model. We examine prospects for
the experimental realization in tilted Bose-Hubbard chains by numerically
simulating the adiabatic state preparation and subsequent time evolution, and
find clear signatures of the low-energy fracton dynamics.
