Cosmology With Axionic-quintessence Coupled with Dark Matter

TL;DR

This paper explores a cosmological model where an axion field from string theory couples with dark matter to explain late-time acceleration, analyzing background evolution and matter growth with observational constraints.

Contribution

It introduces a coupled axion-dark matter model from string theory and constrains it using multiple cosmological observations, highlighting its viability over the cosmological constant.

Findings

Coupled axion models can deviate more from a cosmological constant.

Observational data allows for larger deviations in these models.

The model fits well with current cosmological measurements.

Abstract

We study the possibility of explaining the late time acceleration with an axion field which is coupled with the dark matter sector of the energy budget of the Universe. The axion field arises from the Ramond-Ramond sector of the Type-IIB string theory. We study the background evolution of the Universe as well as the growth of the matter perturbation in the linear regime. We subsequently use the observational data from Sn-Ia, BAO measurements, measurements of the Hubble parameter as well as the observational data for the growth of the matter perturbation to constrain our model. Our results show that coupled axion models are allowed to have larger deviation from cosmological constant by the present observational data.