Cosmology in symmetric teleparallel bumblebee gravity

TL;DR

This paper explores a Lorentz-violating extension of symmetric teleparallel gravity, where a bumblebee field's vacuum expectation value couples to nonmetricity, affecting cosmological evolution.

Contribution

It introduces a local Lorentz violation in STEGR via a bumblebee field coupling to nonmetricity, a novel approach in symmetric teleparallel gravity.

Findings

Lorentz violation influences cosmological dynamics

Coupling affects the evolution of the universe

New insights into gravity modifications in cosmology

Abstract

Symmetric teleparallel gravity (STG) is an alternative description of the gravitational field as an effect of the nonmetricity rather than the curvature of the spacetime. For an specific choice of the symmetric teleparallel lagrangian, the STG dynamics is equivalent to the general relativity (GR), and it is called Symmetric teleparallel equivalent to general relativity (STEGR). We propose a local Lorentz violating dynamics in the gravitational sector in the STEGR framework. The Lorentz violation is trigged by the vacuum expectation value (vev) of the well-known bumblebee field, whose vev couples to the nonmetricity tensor. The effects of such couplings on the cosmological evolution is investigated.