# An overview of quasinormal modes in modified and extended gravity

## TL;DR

This paper reviews how quasinormal modes in various gravity models are affected by modifications, providing qualitative insights and deriving the Regge-Wheeler equation for static, spherically symmetric spacetimes.

## Contribution

It offers a qualitative analysis of quasinormal mode frequencies in extended gravity theories and derives the Regge-Wheeler equation for general static, spherically symmetric metrics.

## Key findings

- Qualitative tendencies of quasinormal mode frequencies in modified gravity.
- Derivation of the Regge-Wheeler equation for general static, spherically symmetric metrics.
- Insights into how gravitational wave observations can probe new physics.

## Abstract

As gravitational waves are now being nearly routinely measured with interferometers, the question of using them to probe new physics becomes increasingly legitimate. In this article, we rely on a well established framework to investigate how the complex frequencies of quasinormal modes are affected by different models. The tendencies are explicitly shown, for both the pulsation and the damping rate. The goal is, at this stage, purely qualitative. This opportunity is also taken to derive the Regge-Wheeler equation for general static and spherically symmetric metrics.