  We study the out-of-equilibrium dynamics of bosonic atoms in a 1D optical
lattice, after the ground-state is excited by a single spontaneous emission
event, i.e. after an absorption and re-emission of a lattice photon. This is an
important fundamental source of decoherence for current experiments, and
understanding the resulting dynamics and changes in the many-body state is
important for controlling heating in quantum simulators. Previously it was
found that in the superfluid regime, simple observables relax to values that
can be described by a thermal distribution on experimental time-scales, and
that this breaks down for strong interactions (in the Mott insulator regime).
Here we expand on this result, investigating the relaxation of the momentum
distribution as a function of time, and discussing the relationship to
eigenstate thermalization. For the strongly interacting limit, we provide an
analytical analysis for the behavior of the system, based on an effective
low-energy Hamiltonian in which the dynamics can be understood based on
correlated doublon-holon pairs.
