CMB Cold Spot from Inflationary Feature Scattering

TL;DR

This paper introduces a feature-scattering mechanism in multi-field inflation models to explain the CMB cold spot, linking inflationary potential features to localized temperature anomalies and potential power spectrum dips.

Contribution

It proposes a novel inflationary scattering mechanism that converts isocurvature fluctuations into curvature fluctuations, explaining the CMB cold spot and related spectral features.

Findings

Predicts localized cold spots in the CMB from inflationary features

Connects the cold spot to a dip in the CMB power spectrum at b120

Provides a new inflationary scenario for observed CMB anomalies

Abstract

We propose a "feature-scattering" mechanism to explain the cosmic microwave background cold spot seen from WMAP and Planck maps. If there are hidden features in the potential of multi-field inflation, the inflationary trajectory can be scattered by such features. The scattering is controlled by the amount of isocurvature fluctuations, and thus can be considered as a mechanism to convert isocurvature fluctuations into curvature fluctuations. This mechanism predicts localized cold spots (instead of hot ones) on the CMB. In addition, it may also bridge a connection between the cold spot and a dip on the CMB power spectrum at $\ell \sim 20$.