Quantitative uniqueness for Schrodinger operator with regular potentials
  We give a sharp upper bound on the vanishing order of solutions to Schrodinger equation with C^1 electric and magnetic potentials on a compact smooth manifold. Our method is based on quantitative Carleman type inequalities developed by Donnelly and Fefferman. It also extends the first author's previous work to the magnetic potential case. 
Laurent Bakri and Jean-Baptiste Casteras
math.AP