New Gravitational Scales in Cosmological Surveys

TL;DR

This paper derives a general framework for understanding scale-dependent modifications to gravity in cosmology, emphasizing the importance of a fundamental mass or length scale, and forecasts how future surveys can constrain these scales.

Contribution

It provides a general derivation of scale-dependence in modified gravity theories, extending previous results beyond scalar field models, and predicts experimental constraints on new fundamental scales.

Findings

Derived a general form of scale-dependence in gravity modifications

Showed results apply beyond Horndeski theories

Forecasted constraints from upcoming cosmological surveys

Abstract

In the quasistatic regime, generic modifications to gravity can give rise to novel scale-dependence of the gravitational field equations. Crucially, the detectability of the new scale-dependent terms hinges upon the existence of an effective mass scale or length scale at which corrections to General Relativity become relevant. Starting from only a few basic principles, we derive the general form of this scale-dependence. Our method recovers results previously known in the specific case of Horndeski gravity, but also shows that they are valid more generally, beyond the regime of scalar field theories. We forecast the constraints that upcoming experiments will place on the existence of a new fundamental mass scale or length scale in cosmology.