In this survey, we review recent results concerning the canonical dispersive flow $e^{ itH}$ led by a Schr\"odinger Hamiltonian $H$. We study, in particular, how the time decay of space $L^p$-norms depends on the frequency localization of the initial datum with respect to the some suitable spherical expansion. A quite complete description of the phenomenon is given in terms of the eigenvalues and eigenfunctions of the restriction of $H$ to the unit sphere, and a comparison with some uncertainty inequality is presented.
Categories: math-ph math.AP math.MP