Gravitational waves in a stringlike fluid cosmology

TL;DR

This paper explores how a stringlike fluid influences gravitational waves and cosmic background anisotropies, offering alternative insights into universe dynamics and addressing age and horizon problems.

Contribution

It extends previous density perturbation studies to gravitational waves, analyzing their behavior in a stringlike fluid cosmology and potential observational signatures.

Findings

Stringlike fluid can cause instabilities in small wavelength gravitational waves.

Traces of the fluid may be detectable in cosmic background radiation anisotropies.

The model offers an alternative explanation for universe age and horizon issues.

Abstract

The coupling of a stringlike fluid with ordinary matter and gravity may lead to a closed Universe with the dynamic of an open one. This can provide an alternative solution for the age and horizon problems. A study of density perturbations of the stringlike fluid indicates the existence of instabilities in the small wavelength limit when it is employed a hydrodynamic approach. Here, we extend this study to gravitational waves, where the hydrodynamical approach plays a less important role, and we argue that traces of the existence of this fluid must be present in the anisotropies of the cosmic background radiation.