On time dependent Schrödinger equations: Global well-posedness and growth of Sobolev norms

If L(t)=H+V(t) where V(t) is a perturbation smooth in time and H is a self-adjoint positive operator whose spectrum can be enclosed in spectral clusters whose distance is increasing, we prove that the Sobolev norms of the solution grow at most as tϵ when t↦∞, for any ϵ>0. If V(t) is analytic in time we improve the bound to (log⁡t)γ, for some γ>0. The proof follows the strategy, due to Howland, Joye and Nenciu, of the adiabatic approximation of the flow. We recover most of known results and obtain new estimates for several models including 1-degree of freedom Schrödinger operators on R and Schrödinger operators on Zoll manifolds.