Effective Field Theory of Large Scale Structure in modified gravity and application to Degenerate Higher-Order Scalar-Tensor theories

TL;DR

This paper extends the effective field theory of large scale structure to modified gravity, addressing ultraviolet divergences in the one-loop matter power spectrum within degenerate higher-order scalar-tensor theories, enabling better observational tests.

Contribution

It introduces new counterterms in the EFT framework to renormalize divergences in modified gravity theories, specifically in degenerate higher-order scalar-tensor models.

Findings

New counterterms successfully renormalize UV divergences.

Renormalized power spectrum aids in testing modified gravity.

Framework applicable to observational comparisons.

Abstract

In modified gravity, the one-loop matter power spectrum exhibits an ultraviolet divergence as shown in the framework of the degenerate higher-order scalar-tensor theory. To address this problem, we extend the effective field theory of large scale structure to modified gravity theories. We find that new counterterms appear and renormalize the ultraviolet divergence as a natural consequence of non-linearity in the modified Poisson equation. The renormalized one-loop matter power spectrum is useful to test modified gravity theories by comparing to observations.