# Signatures of extra dimensions in gravitational waves

## TL;DR

This paper explores how extra spatial dimensions could influence gravitational wave signals, predicting additional polarization modes and high-frequency waves that might be detectable, thus providing potential evidence for higher-dimensional theories.

## Contribution

It derives general wave equations for gravitational waves in higher-dimensional space-times and analyzes observable signatures of extra dimensions in gravitational wave data.

## Key findings

- Existence of a breathing polarization mode due to extra dimensions
- Presence of high-frequency Kaluza-Klein modes in gravitational waves
- Potential observational signatures of extra dimensions in gravitational wave experiments

## Abstract

Considering gravitational waves propagating on the most general 4+N-dimensional space-time, we investigate the effects due to the N extra dimensions on the four-dimensional waves. All wave equations are derived in general and discussed. On Minkowski4 times an arbitrary Ricci-flat compact manifold, we find: a massless wave with an additional polarization, the breathing mode, and extra waves with high frequencies fixed by Kaluza-Klein masses. We discuss whether these two effects could be observed.