Particle Creation in Time-Dependent Gravitational Field and Cosmological Constant

Abstract

Present paper attempt to study the particle production in time-dependent gravitational fields gravity using Cosmological model. In cosmological models, the production of particles plays a central role in explaining the origin of the structures observed in the universe. First we have needed to find an observable of particle density in curved space. After this we introduce our model of the expanding mass shell and discuss its properties. The computation of the number density operator is presented. The purpose of this paper is to show a way, to discover Einstein general Relativity. It is done through analyzing Newtons equation and making the conclusion that space time must not only be realized, but also that it must have curvature in the presence of matter and energy. Initially at t=0 the energy density ?, pressures p, shear ?, cosmological term ? tend all infinite. As t increases the spatial volume increases but the expansion rate decreases. Thus the rate of expansion slows down with increase in time and tends to zero. Again, as t?? the spatial volume V becomes infinitely large. Therefore, at large value of t model gives empty universe. The cosmic scenario starts from a big bang at t=0 and continues until t=?.