Departamento de Gravitación y Teoría de Campos

                          Seminarios 2014

  

                          Instituto de Ciencias Nucleares, UNAM
[ ICN-UNAM]

Jueves 6 de marzo, a las 17:00 hrs en la Sala de Seminarios del ICN

Sujoy Kumar Modak (ICN/UNAM)

Evolution of quantum field in the three stage universe and related physic

We study the evolution of a quantum scalar field in a toy universe which has three stages of evolution, viz., (i) an early (inflationary) de Sitter phase (ii) radiation dominated phase and (iii) late-time (cosmological constant dominated) de Sitter phase. Using Schrodinger picture, the scalar field equations are solved separately for the three stages and matched at the transition points. The boundary conditions are chosen so that field modes in the early de Sitter evolves from Bunch-Davies vacuum state. We determine the (time-dependent) particle content of this quantum state for the entire evolution of the universe and describe the various features both numerically and analytically. We invoke the issue of quantum to classical transition in terms of a classicality parameter which tracks the particle creation and its effect on phase space correlation of the quantum field. Finally, we conclude by discussing the implications of our results on the usual approach of generation of perturbations in the inflationary scenario.