Comment on "Feynman Effective Classical Potential in the Schrodinger   Formulation"
  We comment on the paper "Feynman Effective Classical Potential in the Schrodinger Formulation"[Phys. Rev. Lett. 81, 3303 (1998)]. We show that the results in this paper about the time evolution of a wave packet in a double well potential can be properly explained by resorting to a variational principle for the effective action. A way to improve on these results is also discussed. 
G. Andronico, V. Branchina and D. Zappala'