Can Brans-Dicke Scalar Field Mimic Early Dark Energy?

Abstract

We show that a generalisation of Brand-Dicke (BD) theory can provide a theoretical basis for dark energy at early times. This generalisation is based on introducing a potential for the BD scalar and allowing of the latter to interact with radiation in the radiation-dominated rea. We argue that the model we take up provides a strong theoretical basis for early dark energy (EDE) so that the scalar field can mimic a cosmological constant and quintessence behaviors under slow-roll and non-slow-roll conditions, respectively.