This proves the theorem. 319 320 5 Applications of quantum mechanics 5.4.6 application to Hartree-Fock Ground State We return to the creation and extermination agents of singleparticle states by an arbi y basis. In the approach made over the classic paths are the orthogonal paths of the wave fronts T X. The particle free moving on its mass shells that is to say the four-momentum fullls condition P2 MC 2 its time part p0 is firmly off the module of spatial momentum P0 2 MC P2 2. Part one sect. 3.3.5. If the symmetry action does not reverse the direction of the time operator describes the time development must map the transformed states at each other as well that is the interaction always contains the operator a contract with the electromagnetic density J. This proves the theorem. 319 320 5 Applications of Quantum Mechanics 5.4.6 Application to the Hartree-Fock Ground State We turn back to the creation and annihilation operators of the singleparticle states of an arbi y basis.In the approximation made above the classical orbits are orthogonal trajectories of the wave fronts t x .The particle being free moves on its mass shell that is to say its four-momentum fullls the condition p2 Mc 2 its time component p0 is xed by the modulus of the spatial momentum p0 2 Mc 2 p2.Part One Sect. 3.3.5. If the symmetry action does not reverse the direction of time the operator describing the time evolution must map the transformed states onto each other too viz.The interaction always contains the operator A contracted with the electromagnetic current density j.