Scalar Induced Gravitational Waves from Warm Inflation

TL;DR

This paper explores how warm inflation models with enhanced small-scale curvature perturbations can produce detectable scalar-induced gravitational waves across a broad frequency spectrum, linking early universe inflation to observable signals.

Contribution

It introduces a warm inflation model that generates large curvature perturbations at small scales, leading to scalar-induced gravitational waves within a specific frequency range.

Findings

Generated SIGW spectrum spans 1-10^6 Hz frequencies.

Model predicts detectable signals for current and future GW experiments.

Links primordial black holes formation to gravitational wave signals.

Abstract

Stochastic gravitational waves can be induced from the primordial curvature perturbations generated during inflation, through scalar-tensor mode coupling at the second order of cosmological perturbation theory. Here we discuss a model of warm inflation in which large curvature perturbations are generated at the small scales because of inflaton dissipation. These overdense perturbations then collapse at later epoch to form primordial black holes, as was studied in our earlier work (Ref. \cite{Arya:2019wck}), and therefore may also act as a source to the second-order tensor perturbations. In this study, we calculate the spectrum of these secondary gravitational waves from our warm inflationary model. We find that our model leads to a generation of scalar induced gravitational waves (SIGW) over a frequency range ($1-10^6$) Hz. Further, we discuss the detection possibilities of these SIGWs, taking in account the sensitivity of different ongoing and future gravitational wave experiments.