Particle creation with excited de Sitter modes

Abstract

Recently, we introduced exited de Sitter modes to study the power spectrum that was finite in Krein space quantization and the trans-Plankian corrections because of the exited mode being nonlinear (M. Mohsenzadeh et al. Eur. Phys. J. C, 74, 2920 (2014) doi:10.1140/epjc/s10052-014-2920-5 ). It was shown that the de Sitter limit of corrections reduces to that obtained via several previous conventional methods; moreover, with such modes the space–time symmetry becomes manifest. In this paper, inspired by the Krein method and using exited de Sitter modes as the fundamental initial states during the inflation, we calculate particle creation in the spatially flat Robertson–Walker space–time. It is shown that in de Sitter and Minkowski space–time in the far past time limit, our results coincide with the standard results.