Stochastic gravitational waves from a new type of modified Chaplygin gas

TL;DR

This paper introduces a novel early universe model using a generalized Chaplygin gas, analyzing the resulting stochastic gravitational wave spectrum and constraining the model with observational data.

Contribution

It presents a new scenario for the early universe with a smooth transition from de Sitter to radiation era using a generalized Chaplygin gas, including gravitational wave predictions.

Findings

High-frequency gravitational wave spectrum depends on model parameters.

Model constrained by e-folds, scalar spectral index, and power spectra.

Scalar field description supports the Chaplygin gas model.

Abstract

We propose a new scenario for the early universe where there is a smooth transition between an early de Sitter-like phase and a radiation dominated era. In this model, the matter content is modelled by a new type of generalised Chaplygin gas for the early universe, with an underlying scalar field description. We study the gravitational waves generated by the quantum fluctuations. In particular, we calculate the gravitational wave power spectrum, as it would be measured today, following the method of the Bogoliubov coefficients. We show that the high frequencies region of the spectrum depends strongly on one of the parameters of the model. On the other hand, we use the number of e-folds, along with the power spectra and spectral index of the scalar perturbations, to constrain the model observationally.