A novel approach to the synthesis of nondispersive wave packet solutions to the Klein-Gordon and Dirac equations

A systematic approach to the derivation of exact nondispersive packet solutions to equations modeling relativistic massive particles is introduced. It is based on a novel bidirectional representation used to synthesize localized Brittingham-like solutions to the wave and Maxwell's equations. The theory is applied first to the Klein-Gordon equation; the resulting nondispersive solutions can be used as de Broglie wave packets representing localized massive scalar particles. The resemblance of such solutions to previously reported nondispersive wave packets is discussed and certain subtle aspects of the latter, especially those arising in connection to the correct choice of dispersion relationships and the definition of group velocity, are clarified. The results obtained for the Klein-Gordon equation are also used to provide nondispersive solutions to the Dirac equation which models spin 1/2 massive fermions.