Zero-mass scalar field interactions in the Robertson-Walker universe

Abstract

Considering spherically-symmetric Robertson-Walker metric, we have investigated the problem of zero-mass scalar field interactions in the presence of gravitational field. We have investigated the problem with and without the source term in the wave equation. For a physically realistic solution, the universe should be either open or flat. The physical interpretation of the solutions in connection with the deceleration parameter, the occurrence of “Big Bang” at the initial stage, the energy density, etc. have been investigated.