  We report analytic results for the correlation functions of long-range
quantum Ising models in arbitrary dimension. In particular, we focus on the
long-time evolution and the relevant timescales on which correlations relax to
their equilibrium values. By deriving upper bounds on the correlation functions
in the large-system limit, we prove that a wide separation of timescales,
accompanied by a pronounced prethermalisation plateau, occurs for sufficiently
long-ranged interactions.
