Growth of spherical overdensities in scalar-tensor cosmologies

Understand

The accelerated expansion of the universe is a rather established fact in cosmology and many different models have been proposed as a viable explanation.

• Many of these models are based on the standard general relativistic framework of non-interacting fluids or more recently of coupled (interacting) dark energy models, where dark energy (the scalar field) is coupled to the dark matter component giving rise to a fifth-force.
• An interesting alternative is to couple the scalar field directly to the gravity sector via the Ricci scalar.
• These models are dubbed non-minimally coupled models and give rise to a time-dependent gravitational constant.