About the Power Spectrum Of Primordial Gravitational Waves

Abstract

The primordial gravitational waves have been generated by inflationary amplification of the primordial (quantum) fluctuations. It is true that they have not been recorded directly so far, but their spectrum can help a lot in solving the basic puzzles of the early universe as Inflation (high) energy scale. In the present work, we give a straightforward method to calculate the spectral energy density of the relic gravitons different from that used in e. g. \cite{ mirza04,Latham 2005, Yuki 2006}. The evolution equations are written in terms of the scale factor (instead of conformal time) and are obtained through the Lagrange formalism (instead of the transfer function). The presence of the Hubble parameter allows to calculate the power spectrum in the different dynamical regimes. The corresponding diagram shows in the universe including Cosmological Constant the spectral energy density is noticeably enhanced.Comment: 6 pages, 1 figur, 1 tabl