Quantum Gravity Signatures in the Late-Universe

TL;DR

This paper investigates how connection-based quantum gravity models affect late-universe cosmological observables, showing potential for future experiments to constrain these models and possibly address the $S_8$ tension.

Contribution

It introduces a class of connection-based quantum gravity models and analyzes their impact on cosmological observables, providing constraints and future prospects.

Findings

Certain parameter regions are already excluded by current data.

Future experiments like DESI can further constrain these models.

Some parameter choices may alleviate the $S_8$ tension.

Abstract

We calculate deviations in cosmological observables as a function of parameters in a class of connection-based models of quantum gravity. In this theory non-trivial modifications to the background cosmology can occur due to a distortion of the wave function of the Universe at the transition from matter to dark energy domination (which acts as a "reflection" in connection space). We are able to exclude some regions of parameter space and show with projected constraints that future experiments like DESI will be able to further constrain these models. An interesting feature of this theory is that there exists a region of parameter space that could naturally alleviate the $S_8$ tension.