Gravitational wave generation in hybrid quintessential inflationary models

TL;DR

This paper analyzes gravitational wave production in hybrid quintessential inflationary models, revealing a high-frequency peak in the spectrum that is smaller than in original models, thus complying with nucleosynthesis constraints.

Contribution

It provides a detailed calculation of the gravitational wave spectrum in hybrid models, highlighting the impact of the kination period on the spectrum's features.

Findings

Peak at MHz-GHz frequencies with b5 0 10^{-12}

Peak size smaller than original models

Spectrum consistent with nucleosynthesis constraints

Abstract

We investigate the generation of gravitational waves in the hybrid quintessential inflationary model. The full gravitational-wave energy spectrum is calculated using the method of continuous Bogoliubov coefficients. The post-inflationary kination period, characteristic of quintessential inflationary models, leaves a clear signature on the spectrum, namely, a peak at high frequencies. The maximum of the peak is firmly located at the MHz-GHz region of the spectrum and corresponds to $\Omega_{GW} \simeq 10^{-12}$. This peak is substantially smaller than the one appearing in the gravitational-wave energy spectrum of the original quintessential inflationary model, therefore avoiding any conflict with the nucleosynthesis constraint on $\Omega_\Omega_{GW}$.