Ricerc@Sapienza

We prove that the spectrum of Schr\"odinger operators in three dimensions is purely continuous and coincides with the non-negative semiaxis
for all potentials satisfying a form-subordinate smallness condition.
By developing the method of multipliers, we also establish the absence of point spectrum for Schr\"odinger operators in all dimensions under various alternative hypotheses, still allowing complex-valued potentials with critical singularities.