Dispersion Estimates for Spherical Schr\"odinger Equations with Critical   Angular Momentum
  We derive a dispersion estimate for one-dimensional perturbed radial Schr\"odinger operators where the angular momentum takes the critical value $l=-\frac{1}{2}$. We also derive several new estimates for solutions of the underlying differential equation and investigate the behavior of the Jost function near the edge of the continuous spectrum. 
Markus Holzleitner, Aleksey Kostenko, Gerald Teschl
math.SP math-ph math.AP math.MP