Obtaining the CMB anomalies with a bounce from the contracting phase to inflation

TL;DR

This paper explores a cosmological model where a contracting universe phase precedes inflation, successfully explaining large-scale CMB anomalies like power deficit and hemispherical asymmetry, and discusses implications for eternal inflation.

Contribution

It introduces a bounce from contraction to inflation that accounts for observed CMB anomalies and fits Planck data, offering a novel explanation for large-scale fluctuations.

Findings

Model explains low-l power deficit

Model accounts for hemispherical asymmetry

Fits well with Planck observational data

Abstract

Recent Planck data show the anomalies of CMB fluctuations on large angular scales, which confirms the early observations by WMAP. We continue studying an inflationary model, in which before the slow roll inflation the universe is in a contracting phase, and fit the model with the Planck data. It is showed that this model may generate not only the power deficit at low-l, but also a large hemispherical power asymmetry in CMB. We also discuss the implication of the result to the eternal inflation scenario.