Can Brans–Dicke scalar field mimic early dark energy?

Abstract

We show that a generalization of Brans–Dicke (BD) theory can provide a theoretical basis for dark energy at early times. This generalization is based on introducing a potential for the BD scalar and allowing of the latter to interact with radiation in the radiation-dominated era. 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.