21 cm Power Spectrum for Bimetric Gravity and its Detectability with SKA1-Mid Telescope

TL;DR

This paper explores the potential to detect ghost-free bimetric gravity using the 21 cm power spectrum with SKA1-mid, highlighting how future observations could distinguish it from standard cosmology.

Contribution

It introduces a method to probe ghost-free bimetric gravity through 21 cm cosmology and assesses its detectability with upcoming SKA1-mid observations.

Findings

Potential to distinguish bimetric gravity from $\\Lambda$CDM with SKA1-mid.

Detectability depends on model parameters.

Prospects for testing modified gravity theories with future 21 cm surveys.

Abstract

We consider a modified gravity theory through a special kind of ghost-free bimetric gravity, where one massive spin-2 field interacts with a massless spin-2 field. In this bimetric gravity, the late time cosmic acceleration is achievable. Alongside the background expansion of the Universe, we also study the first-order cosmological perturbations and probe the signature of the bimetric gravity on large cosmological scales. One possible probe is to study the observational signatures of the bimetric gravity through the 21 cm power spectrum. We consider upcoming SKA1-mid antenna telescope specifications to show the prospects of the detectability of the ghost-free bimetric gravity through the 21 cm power spectrum. Depending on the values of the model parameter, there is a possibility to distinguish the ghost-free bimetric gravity from the standard $\Lambda$CDM model with the upcoming SKA1-mid telescope specifications.