Three phases of quantum annealing: Fast, slow, and very slow

Currently, existing quantum annealers have proven themselves as viable technology for the first practical applications in noisy-intermediate-scale-quantum era. However, to fully exploit their capabilities, a comprehensive characterization of finite-time excitations is instrumental. To this end, we develop phase diagram driven Ising chains, from which scaling behavior excess work can be read off function process duration and system size. ``Fast'' processes are well described by Kibble-Zurek mechanism; ``slow'' governed effective Landau-Zener dynamics; ``very slow'' approximated with adiabatic perturbation theory.