Uncovering the History of Cosmic Inflation from Anomalies in Cosmic Microwave Background Spectra

TL;DR

This paper introduces an inflationary model explaining CMB anomalies, predicts observable signals for future missions, and offers a way to differentiate inflation from alternative theories using primordial clock signals.

Contribution

A new inflationary primordial feature model that accounts for CMB anomalies and predicts signals detectable by upcoming observational missions.

Findings

Model explains large and small-scale CMB anomalies.

Future missions can distinguish this model from the Standard Model.

Predicted primordial clock signals can differentiate inflation from alternatives.

Abstract

We propose an inflationary primordial feature model that can explain both the large and small-scale anomalies in the currently measured cosmic microwave background (CMB) anisotropy spectra, revealing a clip of adventurous history of the Universe during its primordial epoch. Although the model is currently statistically indistinguishable from the Standard Model, we show that future observations such as the Simons Observatory and LiteBIRD will complement each other in distinguishing the model differences due to their accurate E-mode polarization measurements, and the PICO mission, if funded, can put stringent constraints on all characteristic properties. The model predicts a signal of classical primordial standard clock, which can also be used to distinguish the inflation and alternative scenarios in a model-independent fashion.