Speaker
Description
We present an extension of the spherical top-hat collapse model in a cosmological framework where the dark sector is composed of two interacting scalar fields. In this setup, one scalar field exhibits rapid oscillations on cosmological timescales and is interpreted as a viable dark matter candidate, while the second scalar field evolves smoothly and represents dark energy in the form of either a canonical quintessence field or a non-canonical phantom field.
We develop a generalized top-hat–like model to investigate the gravitational collapse of a slightly overdense spherical region in the presence of such a coupled dark sector. Particular attention is given to the role of non-minimal coupling between the scalar fields and its impact on the dynamics of collapse.
Our analysis demonstrates that the behavior of dark energy during collapse is highly sensitive to the coupling strength. Specifically, we find that dark energy can exhibit both clustered and unclustered behavior depending on the magnitude of the interaction. These results provide new insights into the role of dark energy in nonlinear structure formation and highlight the importance of dark sector interactions in shaping cosmic evolution.