Constraining modified growth patterns with tomographic surveys

TL;DR

This paper discusses how tomographic surveys can detect deviations in cosmic structure growth caused by modified gravity models, which are otherwise indistinguishable from standard cosmology at the background level.

Contribution

It reviews and synthesizes key results on structure growth in f(R) gravity and the potential of future surveys to identify deviations from General Relativity.

Findings

Modified gravity models induce scale-dependent growth patterns.

Upcoming surveys have significant potential to detect deviations from GR.

The degeneracy at the background level is broken at the perturbation level.

Abstract

Viable models of modified gravity designed to produce cosmic acceleration at the current epoch, closely mimic the $\Lambda$CDM model at the level of background cosmology. However, this degeneracy is generically broken at the level of linear perturbations, where the modifications induce a peculiar scale-dependent pattern. A similar pattern is expected in models of coupled dark energy. I present the main results published in Pogosian and Silvestri [1], on the growth of structure in f(R) theories of gravity, and in Zhao et al. [2], on the potential of upcoming and future tomographic surveys to detect departures from the growth of cosmic structure expected within General Relativity with a cosmological constant.