Detecting quantum gravity in the sky

TL;DR

This paper reviews a novel approach to detecting quantum gravity effects in cosmology by analyzing log-oscillating patterns in the cosmic microwave background, applicable across various models.

Contribution

It introduces a framework where quantum gravity effects manifest as a complex critical exponent affecting all scales, enabling cosmological tests.

Findings

Log-oscillating modulation patterns in the CMB spectrum.

Multi-fractional theory as an example for testing quantum gravity.

Potential to detect quantum gravity signatures at cosmological scales.

Abstract

Getting signatures of quantum gravity is one of the topical lines of research in modern theoretical physics and cosmology. This short review faces this challenge under a novel perspective. Instead of separating quantum-gravity effects of a specific model between UV and IR regimes, we consider a general feature, possibly common to many frameworks, where all scales are affected and spacetime geometry is characterized by a complex critical exponent. This leaves a log-oscillating modulation pattern in the cosmic microwave background spectrum and gives a unique opportunity, illustrated with the example of a multi-fractional theory, to test quantum gravities at cosmological scales.