Probing non-Gaussianity during reheating with SIGW in the LISA band

TL;DR

This paper investigates how non-standard reheating dynamics and primordial non-Gaussianity influence the spectrum of scalar-induced gravitational waves, with potential detectability by future LISA observations.

Contribution

It introduces a detailed analysis of reheating effects on SIGWs considering non-Gaussianity, highlighting features detectable by third-generation interferometers.

Findings

Reheating parameters leave characteristic features in the SIGW spectrum.

Reheating dynamics can significantly suppress or enhance the SIGW signal.

Fisher forecasts show potential detectability of the SIGW spectrum by LISA.

Abstract

We analyse the effects of a non-standard evolution of the Universe during the reheating epoch on the spectrum of scalar-induced gravitational waves (SIGWs) accounting for the presence of primordial non-Gaussianity. We show that given values of $w$ and $c_s^2$ leave characteristic features in the spectrum which can be detectable by third generation interferometers like LISA. In addition, we argue that the specific reheating dynamics can suppress or even enhance the spectrum, with crucial consequences for its detectability. We perform a Fisher forecast for different values of $w$ and different scans to assess the detectability of the signal when different values of the amplitude and central frequency are considered.