Vector-field model with compensated cosmological constant and radiation-dominated FRW phase

TL;DR

This paper introduces a vector-field model with a modified gravity interaction that can counteract a large cosmological constant early on and transition to a matter-dominated universe later, aligning with observed cosmological phases.

Contribution

The paper proposes a novel vector-field model with an added interaction term that dynamically compensates a large cosmological constant and reproduces standard cosmological phases.

Findings

Early phase where the vector-field cancels a Planck-scale cosmological constant

Late phase dominated by relativistic matter energy density

Model reproduces key features of standard cosmological evolution

Abstract

A special model of a massless vector-field is presented, which has an extra modified-gravity-type interaction term in the action. The cosmology of the model is studied with standard noninteracting relativistic matter added. It is found that this cosmology can have an early phase where the vector-field starts to compensate a (Planck-scale) cosmological constant and a late Friedmann-Robertson-Walker (FRW) phase where the relativistic-matter energy density dominates the dynamic vacuum energy density.