Remark on the Kato smoothing effect for Schr\"odinger equation with   superquadratic potentials
  The aim of this note is to extend recent results of Yajima-Zhang \cite{Y-Z1, Y-Z2} on the 1/2- smoothing effect for Schr\"odinger equation with potential growing at infinity faster than quadratically. 
Luc Robbiano (LM-Versailles), Claude Zuily (LM-Orsay)