Non-Gaussian Signatures from the Postinflationary Early Universe

TL;DR

This paper explores how remnants of early universe phase transitions can produce non-Gaussian signals in the CMB, potentially revealing new physics or complicating primordial fluctuation analysis.

Contribution

It calculates the CMB bispectrum from global textures, linking particle physics models to observable non-Gaussian signatures.

Findings

Global textures can generate detectable non-Gaussian signals in the CMB.

Such signals may serve as evidence for new particle physics.

These signatures could also hinder the analysis of primordial fluctuations.

Abstract

We consider contributions to non-Gaussianity of the Cosmic Microwave Background (CMB) from remnants of post-inflationary phase transitions in the very early universe. Such signatures can optimistically be used to discover evidence of new particle physics through cosmological observations. More conservatively they provide a potential obstacle to extracting information about the non-Gaussian nature of primordial density fluctuations from any detection in the CMB. We demonstrate this explicitly by computing the bispectrum from global textures, which may be generated from a wide class of particle physics models.