On the fundamental structure of nature and the unification of forces

A model for the fundamental structure of nature is presented. It is based on two fundamental fermions moving with the velocity of light and differing from each other by the projection of the spin on the momentum vector. The energy of both fermions is proportional to the momentum, which is scaled inversely with the size of a length quantum. All the known forces are a manifestation of one elementary interaction, the spin exchange or spin flip-flop which takes place when two different elementary fermions come together in the same space cell. At this stage the model can explain the properties of the photon as a two-fermion particle and it can be shown that the Dirac theory for relativistic fermions could be deduced from this model. The model predicts that particles like the electron or the quark are stable combinations of a large number of the fundamental fermions, but proof of that prediction has not been given.