Effects on the two-point correlation function from the coupling of quintessence to dark matter

TL;DR

This paper explores how coupling between quintessence dark energy and dark matter affects the two-point correlation function, revealing potential observational signatures like BAO peak enhancement and offering new constraints on dark energy interactions.

Contribution

It introduces a species-dependent coupling model that impacts the correlation function and BAO features, providing an alternative way to constrain dark energy-dark matter coupling.

Findings

Coupling shifts the turnover scale and suppresses the matter power spectrum amplitude.

Non-coupled quintessence models fit the correlation function better than the cosmological constant.

Species-dependent coupling enhances the BAO peak due to increased baryon bias.

Abstract

We investigate the effects of the nonminimal coupling between the scalar field dark energy (quintessence) and the dark matter on the two- point correlation function. It is well known that this coupling shifts the turnover scale as well as suppresses the amplitude of the matter power spectrum. However, these effects are too small to be observed when we limit the coupling strength to be consistent with observations. Since the coupling of quintessence to baryons is strongly constrained, species dependent coupling may arise. This results in a baryon bias that is dif- ferent from unity. Thus, we look over the correlation function in this coupled model. We find that even the non-coupled quintessence model gives the better fit to the correlation function compared to the cosmo- logical constant model. We are also able to observe the enhancement of the baryon acoustic oscillation (BAO) peak due to the increasing bias factor of baryon from this species dependent coupling. In order to avoid the damping effect of the BAO signature in the matter power spectrum due to nonlinear clustering, we consider the coupling effect on the BAO bump in the linear regime. This provides an alternative method to constrain the coupling of dark energy to dark matter.