Gravitational wave background from quintessential inflation and NANOGrav data

TL;DR

This paper explores how scalar fluctuations in quintessential inflation can produce gravitational waves that match NANOGrav data and potentially be detected by LISA, revealing new parameter space for such models.

Contribution

It numerically solves the Mukhanov-Sasaki equation to connect inflationary scalar fluctuations with observable gravitational wave signals, identifying parameter regions compatible with current data.

Findings

Induced gravitational waves can match NANOGrav observations.

Parameter space exists where signals are detectable by LISA.

Model predictions extend to high-frequency regimes.

Abstract

We investigate the production process of induced gravity waves due to large scalar fluctuations in the paradigm of quintessential inflation. We numerically solve the Mukhanov-Sasaki equation for different sets of parameters to obtain the power spectra. We demonstrate that the induced gravity wave signal generated in this framework can falls within the region of the NANOGrav data for chosen values of model parameters. We show that there is an allowed region of parameter space where the effect shifts to high frequency regime relevant to LISA and other available sensitivities.