A new Hamiltonian for a massive relativistic particle with spin one in a   generalized Heisenberg/Schr\"odinger picture
  We consider a particular 4-dimensional generalization of the transition from the Heisenberg to the Schr\"odinger picture. The space-time independent expansion with respect to the unitary irreducible representations of the Lorentz group is applied, as Fourier transformation in the Heisenberg picture, to the states of a massive relativistic particle. A new Hamiltonian operator has been found for such a particle with spin one. 
Rudolf A. Frick