Research on Barrow holographic dark energy part4(Cosmology 2024)

1. Barrow holographic dark energy models in f(Q) symmetric teleparallel gravity with Lambert function distribution(arXiv)

Author : M. Koussour, S. H. Shekh, H. Filali, M. Bennai

Abstract : The paper presents Barrow holographic dark energy (infrared cut-off is the Hubble horizon) suggested by Barrow recently (Physics Letters B 808 (2020): 135643) in an anisotropic Bianchi type-I Universe within the framework of symmetric teleparallel gravity, where the non-metricity scalar Q is responsible for the gravitational interaction. We consider two cases: Interacting and non-interacting models of pressureless dark matter and Barrow holographic dark energy by solving f(Q) symmetric teleparallel field equations. To find the exact solutions of the field equations, we assume that the time-redshift relation follows a Lambert function distribution as t(z)=mt0lg(z), where g(z)=LambertW[lmel−ln(1+z)m], m and l are non-negative constants and t0 represents the age of the Universe. Moreover, we discuss several cosmological parameters such as energy density, equation of state (EoS) and skewness parameters, squared sound speed, and (ωB−ω′B) plane. Finally, we found the values of the deceleration parameter (DP) for the Lambert function distribution as q(z=0)=−0.45 and q(z=−1)=−1 which are consistent with recent observational data, i.e. DP evolves with cosmic time from initial deceleration to late-time acceleration.

2. Lagrangian reconstruction of Barrow holographic dark energy in interacting tachyon model

(arXiv)

Author : Giuseppe Gaetano Luciano, Yang Liu

Abstract : We consider a correspondence between the tachyon dark energy model and Barrow holographic dark energy (BHDE). The latter is a modified scenario based on the application of the holographic principle with Barrow entropy instead of the usual Bekenstein-Hawking one. We reconstruct the dynamics of the tachyon scalar field T in a curved Friedmann-Robertson-Walker Universe both in the presence and absence of interactions between dark energy and matter. As a result, we show that the tachyon field exhibits a non-trivial dynamics. In a flat Universe, T˙2 must always be vanishing, independently of the existence of interaction. This implies ωD=−1 for the equation-of-state parameter, which in turn can be used for modeling the cosmological constant behavior. On the other hand, for a non-flat Universe and various values of Barrow parameter, we find that T˙2 decreases monotonically for increasing cos(Rh/a) and cosh(Rh/a), where Rh and a are the future event horizon and the scale factor, respectively. Specifically, T˙2≥0 for a closed Universe, while T˙2<0 for an open one, which is physically not allowed. We finally comment on the inflation mechanism and Trans-Planckian Censorship Conjecture in BHDE and discuss observational consistency of our model.