Smoothing the $H_0$ tension with a dynamical dark energy model

Abstract

The discrepancy between Planck data and direct measurements of the current expansion rate H0 and the matter fluctuation amplitude S8 has become one of the most intriguing puzzles in cosmology nowadays. The H0 tension has reached 4.2σ in the context of standard cosmology i.e ΛCDM. Therefore, explanations to this issue are mandatory to unveil its secrets. Despite its success, ΛCDM is unable to give a satisfying explanation to the tension problem. Unless some systematic errors might be hidden in the observable measurements, physics beyond the standard model of cosmology must be advocated. In this perspective, we study a phantom dynamical dark energy model as an alternative to ΛCDM in order to explain the aforementioned issues. This phantom model is characterised by one extra parameter, Ω pdde , compared to ΛCDM. We obtain a strong positive correlation between H0 and Ω pdde , for all data combinations. Using Planck measurements together with BAO and Pantheon, we find that the H0 and the S8 tensions are 3σ and 2.6σ, respectively. By introducing a prior on the absolute magnitude, MB, of the SN Ia, the H0 tension decreases to 2.27σ with H0 = 69.76 +0.75 −0.82 km s −1 Mpc −1 and the S8 tension reaches the value 2.37σ with S8 = 0.8269 +0.011 −0.012 .

Negative cosmological constant in the dark energy sector: tests from JWST photometric and spectroscopic observations of high-redshift galaxies

“…refs. [139][140][141][142][143][144][145][146][147][148][149][150][151][152][153] for recent discussions on the subject).…”

Hyperbolic Scenario of Accelerating Universe in Modified Gravity

“…Nonetheless, the DE contender has fine-tuning and cosmic coincidence challenges. To address these issues, various DE alternatives have been presented, such as holographic DE [4][5][6][7][8][9][10][11][12], tachyon [13,14], k-essence [15], quintom [16], quintessence [17], phantom [18][19][20][21][22], and others. Numerous different gravitational theories have been presented in order to comprehend the Universe's current accelerated phase.…”