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