Primordial Non-Gaussianity

TL;DR

This paper reviews the significance of primordial non-Gaussianity in cosmology, emphasizing its potential to reveal physics of the early Universe and its implications for inflationary models.

Contribution

It highlights the importance of non-Gaussianity as a robust prediction of early Universe models and discusses its role in understanding fundamental physics.

Findings

Non-Gaussianity is a key probe of early Universe physics.

Detection of non-Gaussianity could reveal high-energy physics.

Most inflationary models predict detectable levels of non-Gaussianity.

Abstract

Our current understanding of the Universe is established through the pristine measurements of structure in the cosmic microwave background (CMB) and the distribution and shapes of galaxies tracing the large scale structure (LSS) of the Universe. One key ingredient that underlies cosmological observables is that the field that sources the observed structure is assumed to be initially Gaussian with high precision. Nevertheless, a minimal deviation from Gaussianityis perhaps the most robust theoretical prediction of models that explain the observed Universe; itis necessarily present even in the simplest scenarios. In addition, most inflationary models produce far higher levels of non-Gaussianity. Since non-Gaussianity directly probes the dynamics in the early Universe, a detection would present a monumental discovery in cosmology, providing clues about physics at energy scales as high as the GUT scale.