New parametrization of the dark-energy equation of state with a single parameter

Abstract

We propose a novel dark-energy equation-of-state parametrization, with a single parameter $\eta$ that quantifies the deviation from $\Lambda$CDM cosmology. We first confront the scenario with various datasets, from Hubble function (OHD), Pantheon, baryon acoustic oscillations (BAO), and their joint observations, and we show that $\eta$ has a preference for a non-zero value, namely a deviation from $\Lambda$CDM cosmology is favored, although the zero value is marginally inside the 1$\sigma$ confidence level. However, we find that the present Hubble function value acquires a higher value, namely $H_0=66.624_{-0.013}^{+0.011}Km{s}^{-1}Mp{c}^{-1}$, which implies that the $H_0$ tension can be partially alleviated. Additionally, we perform a cosmographic analysis, showing that the universe transits from deceleration to acceleration in the recent cosmological past, nevertheless, in the future, it will not result in a de Sitter phase, since it exhibits a second transition from acceleration to deceleration. Finally, we perform the Statefinder analysis. The scenario behaves similarly to the $\Lambda$CDM paradigm at high redshifts, while the deviation becomes significant at late and recent times and especially in the future.

18 pages, 10 figures

References in corpus (24)

• Dynamics of dark energy
• Raising the bar: new constraints on the Hubble parameter with cosmic chronometers at z$\sim$2
• Baryon Acoustic Oscillations in the Lyα forest of BOSS DR11 quasars
• On the Hubble constant tension in the SNe Ia Pantheon sample
• Hubble parameter measurement constraints on the redshift of the deceleration-acceleration transition, dynamical dark energy, and space curvature
• A parametric model for dark energy
• Modified Gravity and Cosmology: An Update by the CANTATA Network
• On the evolution of the Hubble constant with the SNe Ia Pantheon Sample and Baryon Acoustic Oscillations: a feasibility study for GRB-cosmology in 2030
• The oscillating dark energy: future singularity and coincidence problem
• Is Local $H_0$ At Odds With Dark Energy EFT?
• Probing for dynamics of dark energy and curvature of universe with latest cosmological observations
• Can dark energy be dynamical?
• Constraints on cosmological parameters in power-law cosmology
• Constraining the Dark Energy Equation of State with HII Galaxies
• $f(R)$ gravity in the Jordan Frame as a Paradigm for the Hubble Tension
• A New Equation of State for Dark Energy Model
• A New Class of Parametrization for Dark Energy without Divergence
• Oscillations in the dark energy EoS: new MCMC lessons
• Bouncing cosmology in modified gravity with higher-order curvature terms
• Revisiting the parametrization of Equation of State of Dark Energy via SNIa Data
• The constrained cosmological model in Lyra geometry
• An exponential equation of state of dark energy in the light of 2018 CMB Planck data
• Observational Constraints and Cosmographic Analysis of $f(T,T_G)$ Gravity and Cosmology
• Cosmological tensions in the birthplace of the heliocentric model

Cited by in corpus (9)

• Dark energy in light of the early JWST observations: case for a negative cosmological constant?
• An overview of what current data can (and cannot yet) say about evolving dark energy
• Robustness of dark energy phenomenology across different parameterizations
• Negative cosmological constant in the dark energy sector: tests from JWST photometric and spectroscopic observations of high-redshift galaxies
• Cosmographic Footprints of Dynamical Dark Energy
• Observational Constraints and Cosmographic Analysis of $f(T,T_G)$ Gravity and Cosmology
• Shape of Dark Energy: Constraining Its Evolution with a General Parametrization
• Revisiting CPL with sign-switching density: To cross or not to cross the NECB
• Exploring parametrized dark energy models in interacting scenario