Thermal fluctuations in viscous cosmology

TL;DR

This paper explores thermal fluctuations in viscous cosmology, showing that with specific parameters, a scale-invariant, highly non-Gaussian spectrum can be produced, differing from previous models and testable by future observations.

Contribution

It demonstrates that viscous cosmology can generate a scale-invariant, large non-Gaussianity spectrum with k-independence, contrasting prior models like string gas and holographic cosmology.

Findings

Achieves a scale-invariant power spectrum with large non-Gaussianity.

Finds non-Gaussianity can be k-independent and not suppressed at large scales.

Suggests potential for future observational tests.

Abstract

In this paper we investigate the power spectrum of thermal fluctuations in very early stage of viscous cosmology. When the state parameter as well as the viscous coefficient of a barotropic fluid is properly chosen, a scale invariant spectrum with large non-Gaussianity can be obtained. In contrast to the results previously obtained in string gas cosmology and holographic cosmology, we find the non-Gaussianity in this context can be k-independent such that it is not suppressed at large scale, which is expected to be testified in future observation.