Observational Constraints on the Dark Energy with a Quadratic Equation of State

Abstract

In this study, we introduce a novel late-time effective dark energy model characterized by a quadratic equation of state (EoS) and rigorously examine its observational constraints. Initially, we delve into the background dynamics of this model, tracing the evolution of fluctuations in linear order. Our approach involves substituting the conventional cosmological constant with a dynamically effective dark energy fluid. Leveraging a diverse array of observational datasets encompassing the Planck 2018 Cosmic Microwave Background (CMB), Type Ia Supernovae (SNe), Baryon Acoustic Oscillations (BAO), and a prior on the Hubble constant $H_0$ (R21), we constrain the model parameters. We establish the model's consistency by comparing the Hubble parameter as a function of redshift against observational Hubble data (OHD), benchmarking its performance against the Standard $\Lambda$CDM model. Additionally, our investigation delves into studies of the model's dynamical behavior by computing cosmological parameters such as the deceleration parameter, relative Hubble parameter, and the evolution of the Hubble rate. Furthermore, employing Bayesian analysis, we determine the Bayesian Evidence for our proposed model compared to the reference $\Lambda$CDM model. While our analysis unveils the favorable behavior of the model in various observational tests, the well-known cosmological tensions persist when the full dataset combination is explored.

19 pages, 12 figures, Appendix added

References in corpus (29)

• A Comprehensive Measurement of the Local Value of the Hubble Constant with 1 km/s/Mpc Uncertainty from the Hubble Space Telescope and the SH0ES Team
• In the Realm of the Hubble tension $-$ a Review of Solutions
• The Clustering of the SDSS DR7 Main Galaxy Sample I: A 4 per cent Distance Measure at z=0.15
• Tensions between the Early and the Late Universe
• Quantum Nature of the Big Bang: Improved dynamics
• 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
• KiDS-1000 Cosmology: Cosmic shear constraints and comparison between two point statistics
• The Hubble Hunter's Guide
• Baryon Acoustic Oscillations in the Ly-α forest of BOSS quasars
• Quantum Nature of the Big Bang: An Analytical and Numerical Investigation
• The Expansion of the Universe is Faster than Expected
• Dark Energy Survey Year 3 Results: Cosmology from Cosmic Shear and Robustness to Data Calibration
• Hubble parameter measurement constraints on the redshift of the deceleration-acceleration transition, dynamical dark energy, and space curvature
• Seven hints that early-time new physics alone is not sufficient to solve the Hubble tension
• Hyper Suprime-Cam Year 3 Results: Cosmology from Cosmic Shear Power Spectra
• Why reducing the cosmic sound horizon alone can not fully resolve the Hubble tension
• New Observational $H(z)$ Data from Full-Spectrum Fitting of Cosmic Chronometers in the LEGA-C Survey
• Metastable dark energy models in light of Planck 2018: Alleviating the $H_0$ tension
• Multiple transitions in vacuum dark energy and $H_0$ tension
• Dark Energy as a Critical Phenomenon: a Resolution for Hubble Tension
• A stringy realization of a small and positive cosmological constant in dark bubble cosmology
• Observational constraints on the interacting dark energy - dark matter (IDM) cosmological models
• Identification of Cosmic Voids as Massive Cluster Counterparts
• CMB lensing in a modified $\Lambda$CDM model in light of the $H_0$ tension
• Clockwork Cosmology
• A possible role for the merger of clusters/voids in the cosmological expansion
• Probing extra dimensions through cosmological observations of dark energy
• Non-singular flat universes in braneworld and Loop Quantum Cosmology

Cited by in corpus (4)

• The CosmoVerse White Paper: Addressing observational tensions in cosmology with systematics and fundamental physics
• Robust Preference for Dynamical Dark Energy in DESI BAO and SN Measurements
• The state of the dark energy equation of state circa 2023
• Dynamical dark energy confronted with multiple CMB missions