Is the Spreading of Quantum Mechanical Wave Packets Indeed Inevitable?
  It is demonstrated that -- contrary to the common belief -- it is possible to construct solutions of the non-relativistic Schr\"odinger equation of a free particle, that do not exhibit dispersion. However, it seems that no normalizable wave packets can be built up by their use, so the spreading of the wave packets is indeed inevitable. 
Istv\'an Mayer
quant-ph