  We study the time evolution of correlation functions in long-range
interacting quantum Ising models. For a large class of initial conditions,
exact analytic results are obtained in arbitrary lattice dimension, both for
ferromagnetic and antiferromagnetic coupling, and hence also in the presence of
geometric frustration. In contrast to the nearest-neighbour case, we find that
correlations decay like stretched or compressed exponentials in time. Provided
the long-range character of the interactions is sufficiently strong, pronounced
prethermalization plateaus are observed and relaxation timescales are widely
separated. Specializing to a triangular lattice in two spatial dimensions, we
propose to utilize these results for benchmarking of a recently developed
ion-trap based quantum simulator.
