Condensation of a scalar field non-minimally coupled to gravity in a cosmological context

Abstract

We present a new mechanism to condense a scalar field coupled to the Gauss-Bonnet term. We propose a scenario in which the condensed state will emerge from the background energy density in the late-Universe. During the radiation and dust-dominated eras, the energy density of the scalar field, $\rho_{\varphi}$, decreases at a slower rate than the background density. Eventually, $\rho_{\varphi}$ dominates over the energy density of dust and the scalar field could be condensed. In the condensed phase, we have the de Sitter phase for the universe with $\rho_{\varphi}=3H_0^2M_P^2$. Moreover, we study the cosmological perturbations of the model and explore predictions of the model.