Late-time evolution of the Universe within a two-scalar-field cosmological model

We investigate the late-time evolution of the Universe within a cosmological model in which dark matter and dark energy are identified with two interacting scalar fields. Using methods of qualitative analysis of dynamical systems, we identify all cosmological solutions of this model. We show that viable solutions-in the sense that they correspond to a cosmic evolution in which a long enough matter-dominated era is followed by a current era of accelerated expansion-can be found in several regions of the parameter space. These solutions can be divided into two categories, namely, solutions that evolve to a state of everlasting accelerated expansion, in which the energy density of the dark-matter field rapidly approaches zero and the evolution becomes entirely dominated by the dark-energy field, and solutions in which the stage of accelerated expansion is temporary and the ratio between the energy densities of dark energy and dark matter tends, asymptotically, to a constant nonzero value.

Automated summary

Our research shows that within a cosmological model where dark matter and dark energy are identified with two interacting scalar fields, there are multiple viable cosmological solutions. These solutions can be categorized into everlasting accelerated expansion and temporary accelerated expansion, with distinct behaviors regarding the dominance of dark energy and dark matter energy densities.