Sharp lower bounds for the periodic maximal Schr\"odinger operator in higher dimensions
We prove sharp lower bounds for the Schr\"odinger maximal function on the torus T^d for all dimensions d at least 2, and as a corollary obtain sharp regularity conditions for pointwise convergence of the periodic Schr\"odinger equation. Combined with sufficiency results established by Compaan-Luc\'a-Staffilani, this yi...