Maximum Decay Rate for Finite-Energy Solutions of Nonlinear Schr\"odinger Equations

We give explicit time lower bounds in the Lebesgue spaces for all nontrivial solutions of nonlinear Schr\"odinger equations bounded in the energy space. The result applies for these equations set in any domain of $\R^N,$ including the whole space. This also holds for a large class of nonlinearities, thereby extending the results obtained by Hayashi and Ozawa in \cite{MR91d:35035} and by the author in \cite{beg3}.