Relaxation timescales and prethermalisation in d-dimensional long-range   quantum spin models
  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. 
Michael Kastner and Mauritz van den Worm
cond-mat.stat-mech quant-ph