# Constraining extra-spatial dimensions with observations of GW170817

## TL;DR

This paper investigates how extra spatial dimensions influence neutron star properties and gravitational wave signals, using GW170817 data to set bounds on brane-world parameters and opening new avenues for testing higher-dimensional theories.

## Contribution

It provides the first constraint on brane tension from neutron star observations, linking extra dimensions to gravitational wave data and neutron star properties.

## Key findings

- Neutron star mass-radius relation is affected by extra dimensions.
- Tidal deformability measurements constrain brane tension to >35.1 GeV^4.
- GW170817 data limits parameters of single brane-world models.

## Abstract

We derive the modifications introduced by extra-spatial dimensions beyond the four dimensional spacetime on the macroscopic properties of neutron stars, which in turn affect the gravitational wave spectrum of their binaries. It turns out that the mass-radius relation of the neutron stars, and their tidal deformability, are affected non-trivially by the presence of extra dimensions, and can be used to constrain parameters associated with those dimensions. Implications for I-Love-Q universality relations are also discussed and utilized to obtain a constraint on one such parameter. Importantly, we show, for the first time, that measurements of the component masses and tidal deformabilities of the binary neutron star system GW170817, constrain the brane tension in the single brane-world model of Randall and Sundrum to be greater than $35.1~\textrm{GeV}^{4}$. This work opens up the possibility of making such a constraint more robust by improving the modelling of binaries on the brane in the future.