# Accelerating Universe with a stable extra dimension in cuscuton gravity

## TL;DR

This paper presents a Kaluza-Klein cosmological model within cuscuton gravity that achieves an accelerating universe with a stable extra dimension, utilizing a non-dynamical scalar field and a vector field.

## Contribution

It introduces an exact solution in cuscuton gravity showing accelerated expansion with a stable extra dimension, highlighting the roles of a non-dynamical scalar and a vector field.

## Key findings

- The model describes an accelerating universe with a stable extra dimension.
- The cuscuton scalar field drives acceleration without being dynamical.
- The extra dimension remains stable due to the vector field.

## Abstract

We study Kaluza-Klein cosmology in cuscuton gravity and find an exact solution describing an accelerating 4-dimensional universe with a stable extra dimension. A cuscuton which is a non-dynamical scalar field is responsible for the accelerating expansion and a vector field makes the extra dimensional space stable. Remarkably, the accelerating universe in our model is not exactly de Sitter.