Late time transition in the evolution of the Universe

Abstract

The late time crossover from a power-law to an exponential expansion of the Universe evolution is the major problem in today’s physical cosmology. Unless this critical transition problem is solved, it is not possible to reach a holistic theory of cosmology. In this study, we propose a simple model in the FLRW framework, where dark matter and dark energy interact through a potential. We analytically solve this model and obtain scale factor a(t) from the presented model. Mainly, employing numerical solutions we show that the scale parameter has a hybrid form which includes power and exponential terms. The numerical results clearly show that there is a time crossover tc in the scale factor a(t) curve, which indicates the transition from the power-law to the exponential expansion of the Universe. We fit these unscaled curves and obtain that scale factor behaves as a(t) ∝ t 2/3 below t ≤ tc, and as a(t) ∝ exp(H0t) with H0 = 0.4 and H0 = 0.3 for the relatively weak and strong interactions above t > tc, respectively. It is the first time that we explicitly obtain a hybrid scale factor incorporating the power and exponential terms as a(t) ∝ t 2/3 e H0t . We conclude that the presented model can solve the late time transition problem of the Universe based on dark matter and dark energy interaction. Additionally, we numerically obtain other kinematic parameters depending upon the scale factor. We discuss the limit behaviors of all relevant cosmological parameters. Our results are completely in good agreement with observational data. Finally, we state that this work makes essential steps towards solving a critical outstanding problem of the cosmology, and has a potential to creates a paradigm for future studies in this field.

Holographic Dark Energy and Dark Matter Interaction in Anisotropic Bianchi Type-V Universe

“…Obtained results are also good agreement for late time transition with the theoretical results in Ref. [2] in which they show that DM and DE interaction can explain the catastrophic transition from power law expanding to the inflationary expansion at the late time. Similarly, for the same parameter we plot Hubble parameter H versus cosmic time in Fig.…”

“…Indeed, it is shown in the literature that the interacting models have potential to solve many problems of the cosmology such as singularity, cosmic coincidence and cosmological constant problems [1]- [20]. Additionally, in a more recent study, Aydiner et al also show that the late time transition can be explained based on DE and DM interactions [2]. Although no one knows that the physical origin of the dark sector however it plays more important role on the cosmic evolution of the universe.…”