$\alpha$-vacuum and inflationary bispectrum

TL;DR

This paper explores how the $eta$-vacuum in inflationary cosmology can produce significant non-Gaussian features in the CMB bispectrum, differing from standard vacuum predictions.

Contribution

It demonstrates that the $eta$-vacuum leads to large local non-Gaussianity with distinctive shape features in the inflationary bispectrum.

Findings

$eta$-vacuum induces large local non-Gaussianity.

Distinctive shape of bispectrum compared to standard models.

Correlation between acausal patches in de Sitter space.

Abstract

In this paper, we discuss the non-Guassianity originated from the $\alpha$-vacuum on the CMB anisotropy. For $\alpha$-vacuum, there exist correlation between points in the acausal two patches of de Sitter spactime. Such kind of correlation can lead to large local form non-Guassianity in $\alpha$-vacuum. For the single field slow-roll inflationary scenario, the spacetime is in a quasi-de Sitter phase during the inflation. We will show that the $\alpha$-vacuum in this case will lead to non-Gaussianity with distinguished feature, of a large local form and a very different shape.