Conformal coupling associated with the Noether symmetry and its connection with the $\Lambda$CDM dynamics

Abstract

The aim of the present work is to investigate a non-minimally coupled scalar field model through the Noether symmetry approach, with the radiation, matter and cosmological constant eras being analyzed. The Noether symmetry condition allows a conformal coupling and by means of a change of coordinates in the configuration space the field equations can be reduced to a single equation, which is of the form of the Friedmann equation for the $\Lambda$CDM model. In this way, it is formally shown that the dynamical system can furnish solutions with the same form as those of the $\Lambda$CDM model, although the theory here considered is physically different from the former. The conserved quantity associated with the Noether symmetry can be related to the kinetic term of the scalar field and could constrain the possible deviations of the model from the $\Lambda$CDM picture. Observational constraints on the variation of the gravitational constant can be imposed on the model through the initial condition of the scalar field.