Cosmic Microwave Background Dipole induced by double inflation

TL;DR

This paper proposes that the CMBR dipole may originate from isocurvature perturbations generated during double inflation, offering an alternative to the standard motion-based explanation and constraining inflationary parameters.

Contribution

It introduces a novel interpretation of the CMBR dipole as arising from isocurvature perturbations in a double inflation model, differing from the conventional motion-based view.

Findings

The observed dipole and quadrupole can be explained by the model.

The model constrains the parameters of double inflation.

Provides an alternative explanation to the standard peculiar velocity hypothesis.

Abstract

The observed CMBR dipole is generally interpreted as the consequence of the peculiar motion of the Sun with respect to the reference frame of the CMBR. This article proposes an alternative interpretation in which the observed dipole is the result of isocurvature perturbations on scales larger than the present Hubble radius. These perturbations are produced in the simplest model of double inflation, depending on three parameters. The observed dipole and quadrupole can be explained in this model, while severely constraining its parameters.