Constraining Slow-Roll Inflation in the Presence of Dynamical Dark Energy

TL;DR

This paper analyzes how current cosmological observations constrain inflationary parameters when considering dynamical dark energy, revealing that dark energy models weaken these constraints and allow previously excluded inflation scenarios.

Contribution

It provides a comprehensive analysis of inflationary parameter constraints within dynamical dark energy frameworks using current observational data, extending previous work limited to the mbda CDM model.

Findings

Constraints on mbda CDM are tighter than in dynamical dark energy models.

Dynamical dark energy models relax constraints, allowing blue tilt inflation models.

Large running of the spectral index is possible in both models.

Abstract

In this paper we perform a global analysis of the constraints on the inflationary parameters in the presence of dynamical dark energy models from the current observations, including the three-year Wilkinson Microwave Anisotropy Probe (WMAP3) data, Boomerang-2K2, CBI, VSA, ACBAR, SDSS LRG, 2dFGRS and ESSENCE (192 sample). We use the analytic description of the inflationary power spectra in terms of the Horizon-flow parameters $\{\epsilon_i\}$. With the first order approximation in the slow-roll expansion, we find that the constraints on the Horizon-flow parameters are $\epsilon_1<0.014 (95% C.L.)$ and $\epsilon_2=0.034\pm0.024 (1\sigma)$ in the $\Lambda$CDM model. In the framework of dynamical dark energy models, the constraints become obviously weak, $\epsilon_1<0.022 (95% C.L.)$ and $\epsilon_2=-0.006\pm0.039 (1\sigma)$, and the inflation models with a "blue" tilt, which are excluded about $2\sigma$ in the $\Lambda$CDM model, are allowed now. With the second order approximation, the constraints on the Horizon-flow parameters are significantly relaxed further. If considering the non-zero $\epsilon_3$, the large running of the scalar spectral index is found for the $\Lambda$CDM model, as well as the dynamical dark energy models.