One spectrum to cure them all: Signature from early Universe solves major anomalies and tensions in cosmology

TL;DR

This paper proposes a specific oscillatory feature in the primordial spectrum of quantum fluctuations that addresses multiple cosmological anomalies and tensions, including CMB peak smoothing and Hubble constant discrepancies.

Contribution

It introduces a new primordial spectrum form generated by a scalar field potential, resolving several cosmological tensions simultaneously.

Findings

The proposed spectrum fits Planck, large-scale structure, and local Hubble data well.

It reduces discrepancies between CMB observations and other cosmological measurements.

The model offers a unified solution to multiple longstanding cosmological anomalies.

Abstract

Acoustic peaks in the Cosmic Microwave Background (CMB) temperature spectrum as observed by the Planck satellite appear to be smoother than our expectation from the standard model lensing effect. This anomalous effect can be also mimicked by a spatially closed Universe with a very low value of Hubble constant that consequently aggravates the already existing discordance between cosmological observations. We reconstruct a signature from the early Universe, a particular form of oscillation in the primordial spectrum of quantum fluctuations with a characteristic frequency, that solves all these anomalies. Interestingly, we find this form of the primordial spectrum resolves or substantially subsides, various tensions in the standard model of cosmology in fitting different observations, namely Planck CMB, clustering and weak lensing shear measurements from several large scale structure surveys, local measurements of Hubble constant, and recently estimated age of the Universe from globular clusters. We support our findings phenomenologically, by proposing an analytical form of the primordial spectrum with similar features and demonstrate that it agrees remarkably well with various combinations of cosmological observations. We support further our findings theoretically, by introducing a single scalar field potential for inflation that can generate such a form of the primordial spectrum.