DR. SUJOY KUMAR MODAK

We discuss two separate cases of cosmological particle creation. First we consider the entire evolution history of our Universe, which is approximately taken to be comprised of three phases—the early (inflationary) de-Sitter which transits into a radiation dominated phase and finally going over to the late time de-Sitter. The time-dependent minimally coupled scalar field equations are solved, separately, in these three phases. The field solutions as well as the scale factors corresponding different regions are then matched at two transition points (i.e., de-Sitter¿ radiation¿ de-Sitter transitions). These allow us to discuss issues like particle content, emerging classicality for commoving case in an integrated manner. In the second case, by transforming the radiation dominated FRW Universe into two conformal static patches a curious example of particle creation is presented.