In this paper, we consider three phantom dark energy models, in the context of interaction between the dark components namely cold dark matter (CDM) and dark energy (DE). The first model, known as $w_{\textrm{d}}$CDM can induce a big rip singularity (BR) while the two remaining induce future abrupt events known as the Little Rip (LR) and Little Sibling of the Big Rip (LSBR). These phantom DE models can be distinguished by their equation of state. We invoke a new phenomenon such as the interaction between CDM and DE given that it could solve or alleviate some of the problems encountered in standard cosmology. We aim to find out the effect of such an interaction on the cosmological parameters of the studied models, as well as, the persistence or the disappearance of the singularity and the abrupt events induced by the models under study. We choose an interaction term proportional to DE density, i.e. $Q=λH ρ_{\textrm{d}}$, since the case where $Q\propto ρ_{\textrm{m}}$ could lead to a large scale instability at early time. We also do not claim at all that $Q=λH ρ_{\textrm{d}}$ is the ideal choice since it suffers from a negative CDM density in the future. By the use of a Markov Chain Monte Carlo (MCMC) approach, and by assuming a flat FLRW Universe, we constrain the cosmological parameters of each of the three phantom DE models studied. Furthermore, by the aid of the corrected Akaike Information Criterion ($\text{AIC}_{c}$) tool, we compare our phantom DE models. Finally, a perturbative analysis of phantom DE models under consideration is performed based on the best fit background parameters.
In this work, we study tracker phantom dark energy models with a general parameterization of the scalar potentials. Our analysis also considers the scenario of having both phantom field and the cosmological constant as the dark energy components. A detailed statistical analysis with current cosmological observations shows an increase in the value of the Hubble parameter due to the presence of phantom dark energy but it can not alleviate the Hubble tension completely. Our results using Bayesian methods suggests a decisive evidence in favor of a phantom field over a positive cosmological constan…
Interacting Dark Sector field theory with phantom crossing
Federal University of Paraíba（帕拉伊巴联邦大学）；Government of Paraíba（帕拉伊巴州政府）；University of Science and Technology of China（中国科学技术大学）；University of São Paulo（圣保罗大学）；Yangzhou University（扬州大学）；Shanghai Jiao Tong University（上海交通大学）
We suggest a crucial direct-observational test for measuring distinction between the standard $Λ$CDM model and recently proposed phantom dark energy positive curvature cosmological model. The test is based on the fundamental distance--flux--redshift relation for general Friedmann models. It does not depend on the CMBR data, on the large-scale structure growth models, and also on the value of the Hubble constant $H_0$. Our crucial test can be performed by future gamma-ray burst observations with THESEUS space mission and by using gravitational-wave standard siren observations with modern advanc…
In this work we propose a simple general parametrization scheme of the Hubble parameter for the scalar field dark energy models. In our approach it is possible to incorporate both the quintessence and phantom scalar field in a single analytical scheme and write down relevant cosmological parameters which are independent of the nature of the scalar field. A general condition for the phantom barrier crossing has also been obtained. To test this approach, a well behaved parametrization of the normalized Hubble parameter has been considered and a wide variety of observational data like CMB data, S…
Up-to-date cosmological data analyses have shown that \textit{(a)} a closed universe is preferred by the Planck data at more than $99\%$ CL, and \textit{(b)} interacting scenarios offer a very compelling solution to the Hubble constant tension. In light of these two recent appealing scenarios, we consider here an interacting dark matter-dark energy model with a non-zero spatial curvature component and a freely varying dark energy equation of state in both the quintessential and phantom regimes. When considering Cosmic Microwave Background data only, a phantom and closed universe can perfectly …
Phantom dark energy as a natural selection of evolutionary processes $\hat{\rm a}$ $\textit{la}$ $\textit{genetic algorithm}$ and cosmological tensions
Motivated by the exciting features and a recent proposed general form of the function of non-metricity scalar Q, we investigate the cosmological implications in $f(Q)$ gravity, through the resulting effective dark energy sector, extracting analytical expressions for the dark energy density, equation-of-state parameter and the deceleration parameters. We show that even in the absence of a cosmological constant, the universe exhibits the usual thermal history, with the sequence of matter and dark energy eras, and the dark-energy equation-of-state parameter always lie in the phantom regime. Addit…
Since physics of the dark sector components of the Universe is not yet well-understood, the phenomenological studies of non-minimal interaction in the dark sector could possibly pave the way to theoretical and experimental progress in this direction. Therefore, in this work, we intend to explore some features and consequences of a phenomenological interaction in the dark sector. We use the Planck 2018, BAO, JLA, KiDS and HST data to investigate two extensions of the base $Λ$CDM model, viz., (i) we allow the interaction among vacuum energy and dark matter, namely the I$Λ$CDM model, wherein the …
A Friendly Phantom: Late-time AdS-to-dS transition and cosmological tensions
Istanbul Technical University（伊斯坦布尔理工大学）；University of Ioannina（约阿尼纳大学）；Deutsches Zentrum für Astrophysik（德国天体物理中心）；Odessa National University（敖德萨国立大学）
Dynamical System of Scalar Field from 2-Dimension to 3-D and its Cosmological Implication
我们对大多数流行的标量场暗能量模型，包括（幻影）quintessence，（幻影）tachyon，k-essence和一般的非正则标量场模型，给出了三维动力学自治系统，将动力学变量从变量$(x, y, λ)$变为可观测的相关变量$(w_ϕ, Ω_ϕ, λ)$，并展示了k-本质三维系统可还原为（幻影）快子的那些标量场之间的密切关系，一般的非正则标量场可以归约为（幻影）quintessence，k-本质在某些特殊情况下也可以归约为（幻影）quintessence。对于三维动力系统的应用，我们研究了几种特殊情况，并给出了详细的精确动力学解。本文最后指出，用$(w_ϕ, Ω_ϕ, λ)$代替变量$(x, y, λ)$来表示动力系统的微分方程，用三维来研究动力系统比用二维来研究动力系统更方便，也更有物理意义。我们还提出了一个问题，在空间平坦的单标量场FRW宇宙模型中的混沌行为的可能性在普通物质的存在。
Cosmological Evidence for Dark Axion-Dark Baryon Interactions from Apparent Phantom Crossing
University of Pennsylvania（宾夕法尼亚大学）；Simon Fraser University（西蒙菲莎大学）；Canadian Institute for Theoretical Astrophysics (CITA), University of Toronto（多伦多大学加拿大理论天体物理研究所）
In this work we present a further investigation about Teleparallel Gravity Cosmology. We demonstrate that according the current astrophysical data (CC+Pantheon+BAO samplers with late universe measurements SH0ES+H0LiCOW), an $f(T,B)$ theory can provide another interpretation to the oscillatory behaviour of the dark energy equation of state when applied to late times. The four $f(T,B)$ cosmological viable models proposed here can undergo an epoch of late-time acceleration and reproduce quintessence and phantom regimes with a transition along the phantom-divided line, making this theory a good ap…
