# Imprints of Quantum Gravity in the Cosmic Microwave Background

## TL;DR

This paper investigates how additional massive modes predicted by quantum gravity theories could influence the cosmic microwave background, potentially providing observable signatures if their masses are below the inflationary scale.

## Contribution

It calculates the power spectrum of these massive modes during inflation and discusses their possible imprints on the CMB.

## Key findings

- Massive spin-0 and spin-2 modes exist in quantum gravity spectrum.
- These modes can leave detectable imprints on the CMB.
- Imprints depend on their masses being below the inflationary scale.

## Abstract

It has been shown that the spectrum of quantum gravity contains at least two new modes in addition to the massless graviton: a massive spin-0 and a massive spin-2. We calculate their power spectrum during inflation and we argue that they could leave an imprint in the cosmic microwave background should their masses be below the inflationary scale.