Ponente
Descripción
We revisit Brans-Dicke type cosmologies. In the last years, this alternative has grown in popularity, because of the possibility it may explain cosmological data better than the current ΛCDM paradigm. Besides, as a difference from other scalar-tensor theories, we can assign a clear role to the variation of the scalar field through the cosmic history: a change in the effective Gravitational constant which, despite small, can affect the structure formation and reduce the H0 tension. In addition, if one tries to encapsulate the slow evolution of the BD-field in terms of the current GR paradigm (in which G remains constant), the effective theory that emerges is a variant of the ΛCDM framework in which ρΛ acquires a time-evolving component and plays the role of an effective dynamical vacuum energy density. The effective model, therefore, is not exactly the traditional ΛCDM but, when confronted with cosmological data, it has additional features that let it to be a possible good candidate for the new model of gravity that governs our cosmos
