Modified gravity and dark matter

TL;DR

This paper explores the possibility that modifications to gravity could explain dark matter phenomena, either by replacing dark matter or by introducing new gravitational degrees of freedom that act as dark matter candidates.

Contribution

It provides a summary of minimal models where modified gravity introduces new degrees of freedom that could serve as dark matter candidates.

Findings

Modified gravity can potentially account for some dark matter observations.

New degrees of freedom in gravity models may act as dark matter.

Challenges remain in explaining all astrophysical evidence with modified gravity.

Abstract

The fundamental nature of Dark Matter (DM) has not been established. Indeed, beyond its gravitational effects, DM remains undetected by present experiments. In this situation, it is reasonable to wonder if other alternatives can effectively explain the observations usually associated with the existence of DM. The modification of the gravitational interaction has been studied in this context from many different approaches. However, the large amount of different astrophysical evidences makes difficult to think that modified gravity can account for all these observations. On the other hand, if such a modification introduces new degrees of freedom, they may work as DM candidates. We will summarize the phenomenology of these gravitational dark matter candidates by analyzing minimal models.