Can be gravitational waves markers for an extra-dimension?

TL;DR

This paper proposes that specific features of primordial gravitational waves, such as anomalous polarization amplitudes, could serve as observable markers for the existence of extra spatial dimensions, independent of their size.

Contribution

It introduces a method to identify extra dimensions through gravitational wave signatures generated before compactification, offering a potential observational test for higher-dimensional theories.

Findings

Gravitational waves before compactification have distinct features.

Detection of anomalous polarization could indicate extra dimensions.

Features are independent of the size of the extra dimension.

Abstract

The main issue of the present letter is to fix specific features (which turn out being independent of extradimension size) of gravitational waves generated before a dimensional compactification process. Valuable is the possibility to detect our prediction from gravitational wave experiment without high energy laboratory investigation. In particular we show how gravitational waves can bring information on the number of Universe dimensions. Within the framework of Kaluza-Klein hypotheses, a different morphology arises between waves generated before than the compactification process settled down and ordinary 4-dimensional waves. In the former case the scalar and tensor degrees of freedom can not be resolved. As a consequence if were detected gravitational waves having the feature here predicted (anomalous polarization amplitudes), then they would be reliable markers for the existence of an extra dimension.