Non-minimal coupling of scalar fields in the dark sector and generalization of the top-hat collapse

TL;DR

This paper explores how non-minimal coupling between scalar fields in the dark sector influences gravitational collapse, allowing for both clustered and unclustered dark energy depending on coupling strength.

Contribution

It introduces a model of generalized top-hat collapse with non-minimally coupled scalar fields, analyzing their impact on dark energy clustering behavior.

Findings

Non-minimal coupling affects dark energy clustering.

Both clustered and unclustered dark energy are possible.

Coupling strength determines collapse outcomes.

Abstract

In this article, we propose a new way to handle interactions between two scalar fields in the cosmological backdrop where one scalar field oscillates rapidly in the cosmological time scale while the other does not show any periodic behavior in the same time scale. We have interpreted the rapidly oscillating scalar field as the dark matter candidate while the other scalar field is supposed to be the canonical quintessence field or the non-canonical phantom field. A model of a generalized top-hat-like collapse is developed where the dark sector is composed of the aforementioned scalar fields. We show how the non-minimal coupling in the dark sector affects the gravitational collapse of a slightly overdense spherical patch of the universe. The results show that one can have both unclustered and clustered dark energy in such collapses, the result depends upon the magnitude of the non-minimal coupling strength.