Renormalization of Nonequilibrium Dynamics in FRW Cosmology.pdfVIP

Renormalization of Nonequilibrium Dynamics in FRW Cosmology  J Baacke K Heitmann and C Patzold Fachbereich Physik Universitat Dortmund D Dortmund Germany Intro duction Over the last years there has b een a sustained eort to study the evolution of scalar elds within the context of the early universe These eorts have b een largely fueled by the intro duction of ination which has b een shown to b e a p ossible solution of the horizon and atness problem In addition to mo del building and other discussion of how scalar eld theories can pro duce ination the question of the reheating of the universe the transfer of energy from the inaton mo de to other particle mo des has recieved much attention The reason for this is that the exp onential expansion of during ination makes the universe to b ecome very cold In order to achieve the standard results of nucleosynthesis and other pro cesses the universe must b e reheated to temp eratures ab ove those at which imp ortant pro cesses take place Early eorts to account for the necessary reheating intro duced an ad ho c decay width to the inaton It was assumed that the energy transfer o ccured through single particle decay However more recently it has b een realized that there are much more ecient pro cesses such as parametric res onance in the case of chaotic ination Such mechanisms in which the rate of energy transfer grows exp onentially are referred to generally as pre heating Recently the dynamical pro cesses of ination and preheating are treated within a nonequilibrium formalism It is necessary due to  presented by C Patzold the expansion of the universe and the nature of rapidly evolving dynamics