Imprints of anisotropic inflation on the cosmic microwave background

TL;DR

This paper investigates how anisotropic inflation leaves distinctive imprints on the cosmic microwave background, including unique polarization patterns and off-diagonal correlations, which could serve as signatures of such inflationary models.

Contribution

It introduces the effects of anisotropic inflation on CMB temperature and polarization spectra, highlighting the role of cross correlations as potential observational signatures.

Findings

Off-diagonal TB and EB spectra are induced by anisotropic inflation.

Cross correlations between curvature and tensor perturbations produce unique signatures.

Anisotropic inflation predicts specific off-diagonal correlations in CMB spectra.

Abstract

We study the imprints of anisotropic inflation on the CMB temperature fluctuations and polarizations. The statistical anisotropy stems not only from the direction dependence of curvature and tensor perturbations, but also from the cross correlation between curvature and tensor perturbations, and the linear polarization of tensor perturbations. We show that off-diagonal $TB$ and $EB$ spectrum as well as on- and off-diagonal $TT, EE, BB, TE$ spectrum are induced from anisotropic inflation. We emphasize that the off-diagonal spectrum induced by the cross correlation could be a characteristic signature of anisotropic inflation.