Constraints on the Reheating Parameters after Gauss-Bonnet Inflation from the Primordial Gravitational Waves

Understand

We study the effects of the Gauss-Bonnet term on the energy spectrum of inflationary gravitational waves.

• The models of inflation are classified into two types based on their predictions for the tensor power spectrum: red-tilted ($n_T<0$) and blue-tilted spectra ($n_T>0$), respectively, and then the energy spectra of the gravitational waves are calculated for each type of model.
• We find that the gravitational wave spectra are enhanced depending on the model parameter if the predicted inflationary tensor spectra have a blue tilt, whereas they are suppressed for the spectra that have a red tilt.
• Moreover, we perform the analyses on the reheating parameters involving the temperature, the equation-of-state parameter, and the number of $e$-folds using the gravitational wave spectrum.