SELF-INTERACTING QUANTIZED FIELDS AND PARTICLE CREATION IN ROBERTSON-WALKER UNIVERSES

The effects of self-interaction on quantum particle creation in cosmological models is investigated. The particular models which are considered are that of a scalar field with an interaction Lagrangian of the form LI = -λφ4 and that of an electromagnetic field with an interaction of the form LI = b1(FμνFμν)2 + b2(*FμνFμν)2. In lowest order in the coupling constants, these self-interactions will give rise to the creation of particles in both pairs and in quartets. The contribution which these particles make to the total energy density and pressure of created particles is calculated. It is shown that in general the corrections to these quantities due to the interaction is linear (rather than quadratic) in the coupling constant. The one loop divergences which arise in pair creation are analysed, and the problem of removing them by regularization and renormalization is considered. Estimates are given in particular models for the magnitude of the particle creation arising from self-interaction. © 1979.