The standard cosmological model extended to include spin 1 mode particle production

The quantization of spin 1 field is considered in the flat Robertson-Walker space-time based on a set of normal modes previously determined. Particle creation and annihilation produced by universe expansion are evaluated at a given time. A cosmological model to include the effect of particle production on the gravitational dynamics is then formulated. The scheme is obtained by a slight modification of the Standard Cosmological model via an ansatz on the definition of pressure and energy density. Different examples of the model are solved and the results compared with the corresponding results of the Standard Cosmology.