Acceleration of quantum optimal control theory algorithms with mixing strategies

We propose the use of mixing strategies to accelerate the convergence of the common iterative algorithms utilized in Quantum Optimal Control Theory (QOCT). We show how the non-linear equations of QOCT can be viewed as a "fixed-point" non-linear problem. The iterative algorithms for this class of problems may benefit from mixing strategies, as it happens, e.g. in the quest for th ground-state density in Kohn-Sham density functional theory. We demonstrate, with some numerical examples, how the same mixing schemes utilized in this latter non-linear problem, may significantly accelerate the QOCT iterative procedures.